Only if they are from an Audi TT which have the 5x100 bolt pattern ( same as your car ) Other Audi wheels will not fit, as they are usually 5x112 bolt pattern.
yes
Yes
yes it will
no
Will rims from an 09 Toyota camery fit an 05 jetta
Unfortunately they will not fit on your Jetta. The bolt pattern on the BMW E46 wheels is 5x120, while the bolt pattern on the 2014 VW Jetta is 5x112
VW Audi
Well not sure about the jetta, but the bolt pattern you should be looking for is 5x114. Offsets then should be your next issue. But it can be manipulated with spacers.
Okay, the "tyre number" is 205 55 16 (not 2055516). 205mm wide, 112.75mm from wheel to tread (55% of 205) and the center is 16" wide for wheels. So yes, 16" wheels will fit on your audi a3 and they will fit inside your 205 55 16 tires.
the 5-spoke (fatties) and the older 6-spoke wheels on the TT have a bolt pattern of 5x100, and to my understanding passats after 2001 are 5x120. so i don't think they would fit
No, different bolt pattern.