if you have the skills to do the frame swap then adding some width to the fenders will likely not be an issue.
on the v8 trailblazers the tac module is on the firewall near the brake booster. on the inline 6 4.2l it is built into the ecm i believe. the oil pans on both engines have a hole through them horizontally to allow the front diff and cross shaft to be bolted onto the oil pan. they use the same oil pan on the 2wd models i think. a new oil pan, oil pick up tube, dipstick and tube etc could be used from, say, a camaro. I don't think the block is trailblazer specific. more research on that would be good.
these guys have some good info with lots of oil pan pics etc. what years were what etc. there are 2 parts to the ls primer atrticle on that site.
https://www.pirate4x4.com/tech/billa...SPrimer/Part1/