Yep I dig (6) then (1). (7) was the only one I didn't like.
Any will do. Sometimes I use a pultec, got the curve where I want it, and still need more subs. I'll use something like VOG after the pultec. Point is, any of those will do. Might need to add more processing but it's all good.
The ting is, it is not possible to only affect subs with proper pultecs, as even the lowest frequency setting will go even into the lower mids.