> Do you think John was offended, or felt his role had diminished when his bass lines were replaced with synth bass?
Probably, in a way. But keep in mind that what his role also grew as he programmed drum machines and played more keyboards than in the past. So, one thing makes up for the other.
> Or what about Roger's drum parts being drum machines, thus enabling Queen to replicate easily what the two other members worked hard for.
Actually, the whole point was precisely that machines can NOT replicate a talented professional musician. Freddie, reportedly, said something along the lines of 'drum machines are supposed to be precise, but Roger is guaranteed not to miss a beat.'
And actually, instances of drums being chiefly machines rather than Roger's playing were still a vast minority even for Hot Space or The Works, let alone Innuendo or The Miracle.
> Or how do you think other members felt when someone would do most of the instruments on a song
They got their own 'revenge', most of the time at least.
> in the case of Body Language where Freddie did all but the guitar...
There are also drums there. The bass is Freddie (on synths, of course), but most drums are human there.
> when it is released as a single, since it's basically a solo song, under Queen's name, how do the single royalties work?
Roger and Brian still played there, and John was at least a co-(executive) producer, so it's still a Queen track. Same for, say Bijou: John and Roger are co-producers, even if they didn't write it or play instruments. Or Dear Friends, etc. Only some Flash Gordon tracks escape that.
What I mean is, while publishing royalties obviously went to the writer or writers (in the case of Body Language, Fred wrote the B-Side as well), performing royalties go to the band. In some cases, one band member would contribute a lot less than the others, but in others, he may have done way more, so it's sort of 'fair' and in any case easier for accountants and the members themselves.
John hated Hot Space. Frederick's favourite singer was not Paul Rodgers. Rog didn't compose 'Innuendo.' Witness testimonies are often inaccurate. Wales is not in England. 'Bo Rhap' hasn't got 180 vox.