Temp depends on fish, for clowns and damsels 78 is fine (our heater are automatic for 78, fish do fine)
Sg should be 1.023, 1.025 is a little on the high side for me, but as long as my tank is b/w 1.022 and 1.025 I'm cool (though I add water if I have if it's 1.025). Snail are senstive to sg. Anyway, yes raise your SG before you add any inverts. fish can handle a lower sg, but inverts don't like it.
Clean-up crew does not add to you bio-load, they clean-up more than they waste.
Is your tank long or high? I forget the number of fish per gallon, but 2 clowns and bleeny sound like enough to me (I only have two fish in 55gl). Remember to add slowly, one at a time (well, add the two clowns together). Get an eye on your tank and the levels. The tank will let you know if you have to many fish.
Lr will help with filtration and such. I think the bleeny eats stuff from the lr, so you may need more lr before adding him.
(I'm a little rusty, but I think that's all right)