I'm new to football, played basketball ALOT. In basketball, you could snatch a d2 recruit in d3. Is this the case for football? If so, should you wait til after signings?

They will not drop down in GD, if they are out of your vision (aka are listed as a recruit in the higher division) they won't sign with you... someone with better vision at your level MIGHT be able to get that player but there aren't "pull-downs" in GD and I am pretty sure players stick with the division they're listed anyway.

better vision?

Vision is the "window" or "selection" of recruits visible to you when you search for them at your division level. E.g. when you're at a D2 school you select D2 in the division search criteria. It can change depending on the success or lack thereof of your program. I.e. better Success equals an increased number of higher quality recruits visible to you. Hope this helps.

When you're searching for recruits, you need to keep your projected level set at D-II. If the recruit doesn't show up in the D-II search, he will not sign with you.
Vision means the number of recruits that show up in your D-II search. The more games your team wins over the past 3 seasons, the more of the better recruits will show up in your D-II search. So right now your main goal is to win as many games as possible. If you win 10 or more games this season, you should be able to see more high quality recruits in your recruit search next season. The more wins, the better.