I pulled my seats out this weekend. I love all the space it freed up and the dog seems to enjoy it too. I'm thinking of making a small part to cover over the rear floorboard area and turn it into semi-hidden storage.

I just put the bolts right back in and didn't worry about sealant. When torqued down a little, they should seal just fine, since there shouldn't ever be any kind of pressure on the bottom side. I also pulled the seat belt bracket but left the seat latch for now.

I really like the rubber diamond plate idea.