The Scripts were previously the mains, but now they're finally getting demoted to rear surrounds.
This is what's going in the front:
The picture is an Ascent, but we've got the i version, which is subtly different. You've got the basic idea though.
As for the floor insulation... It's not the sort of thing you can do an A-B comparison on. At minimum, your standard 2x4 single stud, single layer of drywall on either side wall, basic everyone's got one type wall has an STC rating of 30. If you put insulation in it, it goes up to 33. 3 dB of attenuation means basically halving the amount of sound going through. I haven't seen any stats for a cavity with a 16" span, but if you can do it then go for it. If you're not going to have any kind of help who doesn't mind getting really really dirty then I'd say skip it.
Keep in mind though, it's also not something you can go back and do after the fact. For me, knowing that I had skimped on something that I would later be kicking myself over was the thing that finally made me go for it.
As for the can lights issue, if you swap out the floodlights for compact fluorescent lights, then heat buildup shouldn't be an issue. The Commercial Electric brand lights they sell over at Home Depot are really good (at least their 60 watt bulbs are). They come on instantly. From the second juice hits 'em, they're probably at 90-95% of their max brightness.
More importantly for this discussion, they also don't give off anywhere near as much heat as an incandescent. They get warm, and that's about it.