The Trailblazer rear has an odd size bolt pattern that has nothing in common with any other make.
Yeah, I made that mistake too. I thought that all of the GM 6-bolts were the same...
Take a look at to 99-03 S10s. The 4WD axles are the right width for a TF and the 2WD axles are 2" narrower, so one of those might be about right for you. They came with disks or drums, so make sure you get the disks.
If you get the 5-bolt S10 axles, it is the same bolt pattern as most of the MII IFS kits. Can you confirm if that is what you are looking at for an IFS? Other setups exist, but are less common and I would hate to be giving you advice based on the wrong system,
