The valance closer should be welded to the valance just to clear that up. Just make sure that the curve of the valance closer follows the curve of the valance and that the meet tightly together or you will end up with a bit of a mess. Well worth spending the time to get that fitting right.
As for the filler on the floors, all you are doing is giving a neat finish to a solid repair so there is no harm.
All looking good mate and coming together nicely!