A refinish will be easy, there are lots of finishing tutorials on the forum here. Seeing as you like purple, Why not try a heavy metal flake purple & white swirl ?
Extending the neck pickup route is easy, Just make sure you have a good template. Filling the centre pickup route has its problems. As it means that you will have to compensate for the wiring for the neck pup while you fill the middle route. Id leave it & wire it up like a jem.
A fixed bridge conversion on a trem equiped guitar is not a beginers job. Its not as easy as it looks to get it right. Id stick to the trem. You can Lock a trem in position by putting a small wood block between the body & trem block, Then adding 5 heavy springs & turning up the tension on them. Looks like a trem - but is solid as a hard tail (almost)
As for binding, If this is your first attempt at this kinda thing id stay away from binding an already carved top. Also, the Ibanez S models are realy thin on the edges & look awful with a binding (Trust me. customer wouldent listen, insisted on having it bound, Then hated it, Then had it all rounded out into a kinda JS type thing, so it worked out in the end)
As to this comment.
The neck is also very slow when playing like solos. It has a gloss finish but so does my JEM and that thing plays amazing. Maybe it's just dirty but any recommendations here too?
The difference between an SA160 & a jem is similar to that between a bicycle & a harley davidson. Especially if the Jem is a 7 & not a 555.
But mostly it would be set up & overall build quality that is your problem here.
But good luck with the project. Sounds like it could be cool