Technically, you are right: I don't remember Susan being Diane's twin sister to be confirmed in commentary ... of course, there is Jerry saying it directly in comics, but he technically may be mistaken, he is very young and may not have the same knowledge as older immortals (including himself before reset) ... on the other hand, I suspect there is lot more considerably less certain things on this wiki, as we generally assumes characters to be right and speak truth unless there is reason to think they are not.
In any case, do not remove informations this way. I mean, you can remove something which is completely bogus, but if you see information which is uncertain, you should explain that it's uncertain, not remove it completely. Something like what I did with Susan and Diane.
Or you can copy the "citation needed" template from wikipedia.
Any specific reason for changing "FV5" to "V5"? "FV5" is also a typical abbreviation used in the fandom, at least as common as "V5". And "V5" is potentially ambiguous as it could potentially refer to a programmed fifth variant of any of the TFG's base forms, such as MV5 / Male Variant 5 (which was confirmed in a Q&A to be the male Sarah form from Grace's Birthday Party).*
It was mostly because I remembered seeing "V5" more often than "FV5" in the comic: there was a Q&A somewhere where they called it "V5" and remarked on the phrase's ambiguity, but immediately mentioned that since Tedd hasn't had any need to make a fifth male varient (mostly because he's a guy by default and thus his imagination hasn't found anything interesting to do with male forms), the term "V5" was good.
Either way, there's no reason to make the change, so leaving it as is makes more sense. Sorry for any confusion.
I think the idea of fixing grammar and spelling was better. And my decision of keeping Diane reference there was done EXACTLY on the case-by-case basis. I'm not proposing to add entries for other people who already have their page there, but considering the entry was there for years and then moved to separate page ... it shouldn't hurt to leave it there.
Thank you for your grammatical overhaul. This wiki is in need of someone to make the articles more readable and you have made a big difference in helping to rectify the situation.
I'm not sure if you have noticed but all but one of your edits were done while you were not actually logged in to your account. If you're not logged in, the wiki doesn't know the edits you make are actually yours and they get attributed to an anonymous user at your IP address and not to your actual account. In fact, the lone edit that was properly attributed to you, the one you made on this wiki's talk page, is the only reason I can recognize all those other edits you have made as belonging to the same person. Please keep up the good work and do so while logged in if you wish your future contributions to be recognized by the wiki.
Another perk for logged in users is that edits will count toward achievement badges and, in turn, achievement points on this wiki's leaderboard. Just making an account bestows you with a badge worth 10 points ranking you 26th but, had all your edits been made while logged in, you would most probably be in the top 5 on this wiki.
Lastly, I was impressed by your edit count and if you continue to improve the wiki as a logged in user as much as you did as an anonymous one, I may even make you an Administrator on this wiki.