You've got a great start for a kit. My first armor was carpet covered in duct tape. :eek:
The plate you said is the "lower thigh", the name is cuisse - I can spell/type it, but don't ask me how to pronounce it.
Bingo wings are the "floppy" part of the sleeves that pulls away from the body, sort of like wearing a shirt thats 5 sizes too large. Mail would be tailored to fit just like cloth. It's not hard, but it is time consuming. Boy, is it ever time consuming.
The center tasset, the only one I've ever seen mildly similar historically is the Pistoia Altarpiece cuirass. (Mad Matt has a replica here:
http://www.madmattsarmory.com/inv_body.php). I'm very much an armor addict, and it's the only piece I've ever seen with a "center" tasset. The center would be left as just mail, as it's flexible and means you can get in and out of a saddle without exposing too much flesh to enemies. Same reason that they didn't usually have tassets in the rear - some cuirasses have rear faulds, but the only ones that have "complete coverage" would be the "tonlet" styled armors, designed and made specifically for foot combat at tournament. My guess is, since the armor is more of a fantasy style, it's loosely based off of a cod piece from the later ages of armor - there are a number of historical armors that have tassets on both sides and a removable codpiece in the center.
Welcome to the forum!