You got the first part sorta right. 0 dbu = 0 dbv (not dbvu) = .775 v
sorry, all wrong.
0 dBu = 0.7746V
0 dBV = 1V = 2,22 dBu
0 VU = (international) +4 dBu = 1,228V
0 VU = (german broadcast) +6 dBu = 1,55V
VU is a type of average metering as opposed to peak metering which reads instantaneous peaks
correct. but with a 1kHz sine wave only it shoud read the same
but VU is not a reference level
VU = Volume Unit
But dbFS has a maximum of zero and should be the same on all converters. Otherwise there wouldn't be a proper reference between systems. Some people's 0 would be louder than others and that wouldn't make any sense.
it isn't the same on all converters, this is why I never understand people measuring analog gear with their software in dBfs. it says nothing.
there are different standards:
0 dBfs = +14 dBu (Standard used by CBS for the Sony pcm1630 for CD mastering) [thanks Walrus]
0 dBfs = +15 dBu (stupid german broadcast norm. Digidesign even builds a special 192 I/O DA card to reach this norm in germany)
0 dBfs = +18 dBu (IIRC international TV standard)
0 dBfs = +20 dBu (IIRC international cinema standard)
0 dBfs = +24 dBu (some AD/DA converters can manage this, my private home standard
RMS is root mean square which is basically like VU though a bit different. This gives you an average level and will always be several db lower than your peak level.