Are there any specialty parts suppliers for these like there are for Z's ex: motorsportauto, black dragon, arizonazcar...ect..
Unfortunately, no. In the US, the Z is the only JNC with that kind of aftermarket support.
also, will 15x8 0 offset wheels fit on it, thats what I have on my Z and I'd like to get some like it for the Celica
"Fit" is a relative term. They will fit dependent on how much tire stretch you are willing to run. Seen lots of them with a 15x7 zero offset, so if you run 195/50-15's on the 15x8, it should just tuck the tires inside, with the rim lips just poking outside the body.
15x7 zero offset Rewinds: