lt1 rods and crank
#2
Factory crank is stout, factory rods are more rpm limited than power. If staying inside the pcm's limitations and using relatively light pistons then ARP hardware should suffice in them. Really though with the cost of some of tyhe aftermarket options I would probably consider a nice 6" cap screw Scat for $300 before sinking $160 or so into stockers. This would let you run a lighter piston and that is a lot less stress on the bottomend.
#3
So long as they aren't subject to a lot of RPM, the stock rods with good hard ware will take some abuse. We ran a set in a 383 that had a cheap cast crank, stock rods fitted with ARP hardware and TRW pistons, the car ran for years with two 150 shots (one on the intake, another hidden in the fender). The car never saw a lot of RPM and had a fairly small cam for a 383, (CC305) so it never had to be ramped up that hard. The motor was still running fine after 5 years of abuse when it was pulled apart. Far as stock Crank, Jason Warren was ran a 9.3@140+ with one in his 355 on gas.