These are just my takes on how I would do a fan canon Fallout wiki;
Primary canon would be Fallout 1 and 2.
I would consider FNV also canon though FO3 references should be ignored. I would also consider the DLCs canon even if some like OWB have a lot of ridiculous moments (FO2 also had a lot of pop culture and absurd elements)
Tactics being canon is a subject of debate.
At this point I would not consider any of the the fan creations as their content is contradicted here and there by the official games.
I do like Fallout Resurrection and it is probably a fan mod that is the closest to Fallout 1 and 2 but there are still a number of incompatibilities. The Hub was for example not destroyed in Fallout 1.
Fallout Yesterday. How much I like the idea of Black Isle's Fallout 3 being made as a fan project so we can finally play it I don't think it will ever be fully like Black Isle had planned back in the day, so yeah it is not canon.
Fallout Sonora. The same situation.
I would perhaps do a Lucasfilm approach to the canon though, that elements within these games that do not contradict Fallout 1, 2, and FNV should can be considered B or C tier canon unless an official game contradicts it. I know that is unlikely but I want the option to remain open.
We could include New Vegas and Van Buren at the same time and just come up with explanations for the inconsistencies. Same with some fan projects.
The biggest problems I can see with Van Buren and New Vegas contradicting is Hoover Dam, Joshua Graham, and Arcade Gannon.
The year that the NCR found the dam in cannon is one year after Kimball's election. So what if, the Legion kept growing and pushing the NCR further back. Kimball decides that the Hoover Dam should be converted into a military outpost and evicts all of the citizens a year after he's put in office. The Legion and BoS had both attacked the dam before in Van Buren, I don't see why we should retcon the brotherhood attacking the dam, but the Legion in cannon didn't even discover the dam until after the NCR showed up. Correct me if I'm wrong, but I believe the developers were thinking that the Legion shouldn't have attacked the dam yet because they were saving them for Fallout 4. So we could just pretend that doesn't happen in Van Buren. I think there was also going to be FEV in the lower levels of the dam... No. We don't need that. And lastly, for what I can remember, Arcade Gannon would've been a companion found in the dam. Arcade didn't have much of a bio in the design documents, just that he used to be Enclave, so I think we can just pretend Arcade wasn't there.
Joshua Graham was the Hanged Man, exiled from the Legion, I forget why though. What Joshua was somehow captured by an enemy who held an execution for Joshua's crimes. So the Hanged Man could exist, while still being Legion. After the end of the game, Joshua goes back to Caesar and resumes position as legate. I'm he'd be punished for his leap of absence, but at least it wouldn't contradict cannon.
There's also the whole, New Canaan/Jericho thing. I don't think Black Isle even knew what they were doing there, so we'll just say New Canaan wasn't destroyed yet. Along with any tribes in Van Buren that have a different fate in New Vegas.
For Fallout Resurrection, we could just ignore that the Hub wasn't destroyed, pretend nothing says that in the game.
Of course, most people aren't willing to just pretend some parts of a game aren't cannon, and especially if you're going to make a wiki it'd be pretty hard. Maybe the people making the wiki could have a council and the council decides which elements of which games are and aren't cannon.