Hey man!
I wouldnt go any bigger on the bore if it isnt required, go the 86.5mm as others have said incase you need to rebore again in the future
Get some 740cc or 800cc injectors to get the most of out a 3540 1.06
the gate might be a tad small, if the rest of your accessories are 25 then use a 25 balancer
otherwise you could invest in a ati or ross (i dont think you will be reving it to hard given your still using stock rods)
Headgasket will depend on the comp ratio your after, most likely a 1.2mm
For peace of mind, you could always put an aftermarket set of gears in your oil pump or if the current one is worn out
water pumps are only like $100 for the 30?