I see my previous reply was unclear
It looks like what you are building is an extension to ASDF
not an extension but a patch
that hooks it into an editor
yes
(perhaps specifically the lispworks IDE?).
No. I use lispworks IDE for Lispworks and EMACS (via SWANK callback) for SBCL. EMACS/SWANK should work with all lisps supported by SLIME.