Lower windshield moulding is that strip of trim between the dash housing and the windshield. IIRC, its about an inch wide and unbolts with phillips head screws. So that piece of trim and the speaker grille will be painted to match the dash pad.
Though there were some funky cloth insert standard seats in '65, I don't think there were any like that in '66. So your bench seat car should have had the all parchment (with different textured inserts like all '66s). Here's a company that has the seat covers.
http://www.restoremustangs.com/Bench-Ful...;search_group=0
If your original bench is gone and you want to go back, it may be possible to make one. They really were pretty much two buckets bridged together.
Though I'm a purist at heart, if your bench seat is gone I would be inclined to restore it with buckets and add a console. I really like consoles in those cars to dress up the interior a little.
Good luck.
TOM