I've seen the Hasegawa B6N2 at a local hobby shop (The Hobby Stop) in Rock Hill, SC, recently for around $38, and they had about three of them, so it's pretty easy to find around these parts.
The Seversky looks as though it might be a Williams Brothers kit, but I can't tell for sure from the box, due to the angle of the photo. I'm pretty sure I've seen it at the same local hobby shop for about $25, and, if I remember correctly, they had about four of those kits.
The Aoshima B5N2 kit is a pretty common one at the same hobby shop. I think it was going for around $25, too, but it's been about a month since I was last there, so I don't remember for sure about the price.
You look like you got a pretty danged nice haul, though!! Way to go!! Hopefully, the other forum members will get you the information on the other kits soon.
Gary
Devil Dawg
On The Bench: Tamiya 1/32nd Mitsubishi A6M5 Model 52 Zeke For Japanese Group Build
Build one at a time? Hah! That'll be the day!!