[LS short box]

If you change your mind on a cam upgrade you need upgraded valve springs and push rods. You didn't say many miles on the engine but if its a lot I would pull the timing cover check the timing chain for wear. Also if lots of miles maybe a new oil pump. Check oil seepage from the rear main seal and oil pan.
In regards to the oil pan I would not run a pan that hangs down below the cross member.
I like Howell Fuel Injection and Speartech harnesses. You can send them your ECM and they can reprogram as needed. They can set your shift points if you send them your tire diameter and gear ratio. Shift Works sells a trans tail shaft conversion that includes a mechanical speedo drive but its not cheap.
I would go with a baffled 87 tank. They aren't expensive.
My thoughts on LS swaps is that use as many "stock" parts as possible so if something goes bad parts are available at the nearest parts store.
Good luck with your swap.