No, none of them are federal contractors. They are direct employees but not sworn law enforcement. You apply on USAJobs.gov and go to FLETC for training, although the topics are very different than sworn/1811s going there, ex no firearms training. Some airports, SFO being the only notable one iirc, choose to contract their own security as an airport/municipal contract with TSA approval, in which case TSA only staffs some executive/oversight roles. Occasionally you see staff in green DHS uniforms rather than blue TSA ones, such as the dog handlers, however I believe they are still under TSA, not sure if they are armed though as it is not the typical blue TSO/STSO uniform.

I assume the technology part (secure flight) is heavily contractor run like most govt/defense technology, one of my old coworkers was briefly involved in that. Didn't say anything interesting about it beyond that they used one way fibers to upload the data into classified systems for processing without anything going back to the main system. The basic workings of the system are described in the SORN/PIA notices though IDK how up to date they keep them.