One thing you haven't stated (and no one has asked) is what kind of VB will you be using? THis will have a great effect on weather you stand a chance of over spinning the front drum.
If you plan on using a VB that does not have a LBA in first gear then I hihgly recomend a billet front drum. Most, manual VB's do not have LBA in first gear. All stock VB's (even those with a shift kit) reatain the LBA in first gear.
I have never knocked out a good working sprag so I can't tell you weather pressing in another factory one will last or not. Cheap insurance to not have to open it up after 5 passes would be a bolt in sprag.
If the bushings look good, I don't bother replacing them. Is it right? Probably not, But I've gotten away with every time so take that with a grain of salt and use your best judgement.
Cleaning the inside? I'm assuming you don't have accsess to a Hot Tank? Works great just be sure the "soap" is aluminum safe. If no tank, accetone or laquer thinner will work fine as will brake clean but that could get expensive. Tranny fluid is a fairly high detergent oil so things should clean up easily.
As for assy lube, beleive it or not, all I've ever used is good ol' petrolium jelly. Heard that trick form my auto trans instructor back in colledge. Never let me down yet.
One other thing I have yet to hear mentioned is, Do you have a lip seal tool? They aren't expensive and kinda a must have. It's really the only "transimission tool" I have ever bought. I can;t imagine how you will gett the seals and drums in correctly with out one.
