WMG / Rune Factory 4

Doug isn't the only one who from his tribe who survived the massacre by the Sechs Empire.

The other dwarf who survived was Zaid. They both have silver eyes (Doug's are more obvious in his official artwork), which Zaid constantly brags as a unique trait of his tribe. Zaid also does not seem have any living friends or relatives from his tribe making it possible that they, along with Doug's biological family, were murdered by the Sechs Empire.

• In addition, Zaid notes at one point that the reason he lives in the settlement is because his original home was massacred by humans. That those responsible are the Sechs Empire, and that he wasn't taken in by the same lies that duped Doug, is not that far of a stretch.

Illuminata was initially going to be a marriage candidate.

Outside of universe, it's very difficult to explain away the fact she has a swimsuit and pajamas in art by other reasons - outfits that only the main marriage candidates have - as simply coincidence, when the other non-candidate villagers could've had them in their artwork too, but do not. (Nancy has explicitly been mentioned to wear a swimsuit in dialogue, but she's never shown in one in art.) Illuminata's also the only villager whose relationship status is explicitly known to be single. While it would make sense in-character for her to be too obsessed with finding cases to solve to have a relationship, it's a bit hard to shake these things as just being there for no reason.

• This does seem somewhat likely, given the surprisingly limited number of town events mainly focused on her - if they were mainly revolving around her obsession with being a detective, you'd think there'd at least be some repeatable events involving her detective obsession in addition to the one-time events (and some of the events she's involved in also raise this being a possibility - the events involving her that require Amber to be in town are not prerequisites for Amber's marriage event). Additionally, there's one line of dialogue where she mentions that she's looking for a "Special someone". Methinks that had she been included as a marriage candidate, the prerequisite events to trigger the marriage event would likely have been "Introducing Amber Watson", "Florist by Day, Sleuth by Night", and "It's a Mystery!". The only reasons I can think of for her not being included would be that if they did include her and didn't cut one of the other female marriage candidates, they would've had to add a 7th male marriage candidate - and given that the only single male character is Volkanon...I don't entirely blame them.
  • There's also Bado, he never mentions a wife anywhere.
    • Really? Huh. Maybe that would've been a better choice. Does raise the question of what Bado's events would be, since unless I'm mistaken, I can't really think of any events that he was involved in (although it's been a while since I last played this game...)

If you're playing as Lest, the canon pairing is Amber x Lest

Thus explained the green haired offspring.

• Alternatively, it is possible the green hair gen is recessive that is shown in your offspring.

The canon main character is Frey

It explains the Game-Favored Gender. Look at is this way. This is not the first RF game that offered player to choose gender, it is the first RF game to have a female main character. The male character is simply added for the male demographic.

The canon main character is Lest.

it's easy for Venti to have mistaken Lest for Arthur. They look somewhat alike, and are both male. Frey looks nothing like Arthur, and is a different gender.

The canon pairing is Lest x Frey

In the previous game, the main pairing is shown in the title...

• Frey and Lest might be coexist in the same universe, they aren't alternate universe counterpart. Either of them could be tasked to go to Selphia, while the other stayed in their home town.
• I doubt it. In the third arc, you'll meet the ancestor of Lest or Frey's who helped the four guardians and though they don't have a sprite, their model is that of the opposite main character's gender that you don't choose. (Frey if you play as Lest and vice versa).
  • Third arc doesn't show any such ancestor. You do meet the main character you don't choose in the forest of beginnings, but there's no dialogue, and it's more of a case of "what you could have been".

The canon romantical interest is Venti

Well, this is WMG, so...

• Consider that Ventuswill follows all the main traits as other "canon" love interests do for the PC. This being: Being the first person they meet after realizing they have amnesia, giving them a farm and a home, and the game pushes you to spend time with her.
  • Also, the entire story revolves around her, and it is -heavily- implied she does love you (and in not so subtle terms), and the PC goes to great lengths to help her.
    • Methinks that the love between Venti and Lest/Frey is more akin to that of a grandparent and a grandchild - a nonromantic type.
    • There’s also the basic fact that Venti isn’t a bachelorette. If it can’t happen in the game, it isn’t remotely canon.

Ragnarok, the last boss of the Rune Prana is Ethelberd's phantom

Seem pretty obvious that the two are connect since Ragnarok is a Pallate Swap of Etherbert, who dies and as a result went to the Forest of Beginnings, where the Main Character finds him. His place as the final boss of the Rune Prana/Forest of Beginnings might be because he used some of Ventuswill's runes, and used Etherlink on Ventuswill so defeating him helped pave the way to Venti's rescue.

In line with the above, Ethelberd's monster class is 'Little Emperor'.

Because it would be incredibly appropriate.

Pico is not a ghost.

"Ghosts don't exist" -Forte

• Pico is an puppet controlled by Dolce. As a Guardian, her boss form was called Marionetta, a puppeteer. It would make sense if Pico were an ventriloquist dummy, able to say all the things Dolce won't say herself. It's entirely possible that not even Dolce remembers this, and Pico has become a full-blown split personality.

Selphy from Rune Factory Frontier was the original princess for Selphia.

Besides the similarities in the names, Selphia is an independent kingdom within Norad that seems to be ruled by a representative of the Norad royalty for dealing with public affairs alongside Ventuswill who deals with the overall welfare of the land. When Selphy got bored of being a princess and left, tourism dropped so Arthur was sent as the replacement monarch.

Jones and Nancy's love is a hoax

As pointed out in this video The way that Jones and Nancy react to the love potion is quite peculiar. Jones recognizes it from when he was a medical student. Nancy is one that knows what it is (besides Arthur) and she says that love should not be acquired through potions. Where did they meet? When Jones was a medical student.

In addition, Nancy will sometimes say

'When courting your special someone, you should maintain a respectful, clean relationship. Not that I have room to talk. Oh ho ho! ♪'

Is it possible that Nancy tricked Jones using a love potion?

• I always assumed that they became a couple because someone else used a Love Potion on her, and Jones helped her while she was under the influence of it - unless she used it before Jones had been informed of one, odds of this WMG being true are slim, since if Nancy was willing to use one on Jones, it would imply that she loved him.

Pico is Dolce's dead older sister.

Pico died at age ten at most, and Dolce was born soon after. Even though she was dead, Pico still cared for her little sister and so attached herself to Dolce. Whenever Dolce told her parents about Pico, they denied it because remembering Pico was too painful for them.

• Considering how often Pico tries to hit on Dolce and encourages her to wear more transparent clothing, I would certainly hope they're not related.

In the case of Frey/Leon their ‘canon’ child is Noel.

Noel can be Leon spelled backwards, after all.