Taxing 28: The least-skills solution (7 skills total) uses 3 builders, and no blockers or bombers, and can be adapted to a no-bashers solution. Both the climber and miner can be avoided with a solution that starts by building up from the floor.
1 floater, 3 builders.(edit: Wow, Taxing can be done with no climbers. That's a nice little surprise
)
Mayhem 1: With no climbers available, there's little opportunity (besides the final part) to save builders through steel glitches. I got this down to 15 builders (replay attached - for reference, the least-skills solution uses 17).
1 floater, 15 builders.Mayhem 19: I don't know how namida plans on doing this with 5 builders, since the best I can manage is 7
(replay attached)
3 bombers, 7 builders.Mayhem 29: Rather annoyingly, the tight skill and % limits appear to require one more digger and blocker than I'd like. Replays attached with 10 builders and no bashers.
3 blockers, 10 builders, 1 digger.This leaves Mayhem
29 and 30, which I'll try now.
EDIT: Mayhem 30 almost certainly comes to 8 builders. I'll have to run through and confirm this, which may take a while...