I listened to the interview with Omar once more, and he says that he played the fills. And since he actually was the there, I take that as a fact.
Well, Terry said the fills are his here: https://archive.org/details/modern-drummer-issue-79/page/n63/mode/2up?q=dire+straits
And Neil Dorfsman here: https://www.mixonline.com/recording/classic-tracks/classic-tracks-dire-straits-money-nothing-372507
Both were there, and it's two versus one... So they are more likely to be Terry's.
Thanks for the links.
I wonder if there is the possibility that they used the same click track, the same project/tape, and put Omar on other new unused tracks, rather than replacing Terrys or starting a new project, whilst MK recorded a guide guitar part, just so it felt like it was a new recording to Omar, all whilst keeping Terry’s tracks (muted), and the rest of the band (muted) that they could then mix in together later on. Without Omar really being told or aware? A more non-destructive approach so they had more options for mixing later maybe? I suppose that is if they got Omar to do a take without any toms as well?
That would have been possible if they had at least two 24-track tape machines, with which they could create slave reels with individual elements and so on... And select the best bits
But in Dire Straits' case on BIA, they had only one 24-track digital recorder at hand, which they cut the whole album on. Plus, they were out in Montserrat and thousands of miles away from any replacements...
Drums would take a lot of the tracks on the 24-track: at least 9 or 10 for a single drum performance - kick, snare, hi-hat, 2 toms, 2 overhead, 2 room mics...
Basically, there wouldn't be enough room on tape to keep both Terry's and Omar's drum performances in full... Hence decisions have to be made as to what bits to keep and what to remove, to allow space on tape for other overdubs.
With Terry, they felt they didn't have the right feel with his drum parts so they were mostly erased, allowing room for Omar to add his parts.
Hope that makes sense! Without trying to be too technical.