I was always told take a piece of poster board. Push it down onto the recesses so it makes an outline of the cavity then cut along the lines and use that as your template.
I know Maiden uses a seymour duncan JB or JB junior in the bridge , then duncan hotrails in their neck and middle. Im sure you could fit a battery in your guitar. Metallica uses EMG 81's and i think SA's if the use singles which are both active.....
the body it came off of used a tune-o-matic stoptail setup. Sounds like you got the one off of e-bay. Be careful with that thing or youll end up snapping the headstock off.
My school actually has a spray booth in the basement artrooms complete with fans and everything. Too bad they only use it for glazing ceramics. I should bring in my spraygun and let loose.
Ive seen a steel conversion nut for turning a regular guitar into a slide guitar at my local shop , you just drop it in the old one used to be. Maybe you could snag one of those.
I have a set of 3x3 black prs style locking tuners , if you want me to send pics of them i will..
Id like to get $32 out of them so i can buy some new grovers.