Unless the RF 100-400mm comes in at a low price and a super compact size, I don't see much point of it alongside the RF 100-500mm. The latter is more expensive than the EF 100-400 II, when that lens was introduced... But not a great deal more. Plus the RF 100-500 appears to be about the same size and weight as the EF 100-400 II.... but with 20% more reach.
I'm also interested in an RF 15-35mm f/4L. That wou!ld be a great addition and is probably close to the widest possible that wouldn't need a convex front element and be able to use standard filters.
The 70-135mm f/2, if it's L quality and as good as some other RF lenses, might serve well in place of a number of portrait primes. f/2 is close enough to f1.8 that it might take the place of an 85mm f/1.8, while the zoom also covers for the 100mm f/2 and 135mm f/2.
Canon might make an R5 owner of me yet!