well, i'd add a termie & at least one more scout to each unit for scoring purposes... as for the termies, i'd go for a 2:1 ratio between claws & hammer + shields.
the assault squad really, really needs a veteran sergeant to do anything to MEQ units. generally speaking assault marines are actually one of the worst combat units... they are only slightly better than tac marines and move faster. that's it really! every other dedicated assault unit gets an edge such as furious assault, chain axes/choppas, power toys, rending and such. for this reason, i'd honestly drop the unit to 6 +1 flamer and a vet tooled however you like... a nice cheap counter assault unit.
the scouts are your real assault boyz in a marine army! cheap and yet they get just as many attacks as assault marines. infiltrate helps them out a bit getting into position for the first charge...
go for a full scout unit and add in the vet w/power fist + teleport homer simply to give you the edge should ever choose to deep strike the termies...
as for the heavy bolter in the transported squad... personally i'm not a fan of it, but for marines it is pretty damn cheap at least... still though, just so long as you realise you're paying those 5pts for a gun you're likely to shoot only once or twice!
hope this helps,
cheers!