Hi I can help a bit
1) yes the tyres will fit your kit rims,
2) I use Mr O foams inserts, but you can go with schumacker mediums or softs I think,
3) this time of year a set of silvers should last you the day on the back, it's good to have a spare set
on my laser I use greens on the front,now used them for three meetings (I'm going to try silvers on the front but I like my car very forgiving...as I'm getting a bit old for knife edge reactions
)
You could also have a set of rear greens glued up if you wish but for the last few meetings I have used silvers on the back every time,
4) can't realy help there
My advice is biased on a ZX5 that I have had some quite good results with at stotfold in the last couple of months, but other's may well offer diffrent advice to me