Use line range within a fold

Is it possible to restrict line range to within current fold? Say I want to do a substitution from second line through end of fold i.e.

2,$s/str/replace/ 

but I want it to apply to current fold only.

There are motions for jumping to the beginning of the current fold (:help [z) or to its end (:help ]z) but they don't have equivalent marks. If that were the case, one could do this with the imaginary '* mark:

:2,'*s/str/replace/

but that mark doesn't exist so it won't work.

One way to achieve what you want would be to visually select the area:

]zv[zj

and then do your substitution on the visual selection:

:'<,'>s/str/replace/

with the range '<,'> automatically inserted for you.

Or you could go the "grok vi" way and place manual marks:

]zme[zmb

before using them in your substitution:

:'b+,'es/str/replace/

but it seems less optimal than the "visual way".

Another solution would be to close the fold:

zc

and do the substitution on the closed fold, with confirmation so that you can skip the substitutions that occur on the first line:

:s/str/replace/c

So there are two approaches, here: one where care is put into defining the exact range and one where care is put into not substituting the wrong thing.