well, i haven't really looked in the GSA catalogue as of late, but i know that barco currently supplies all of the pulaskies for the USFS. I have seen collins, council, and true-temper pulaskis as well, but i suspect they are of an older date. for that matter, we have a few kelly flint edge double bits with "USFS" stamped on them, as well as a vaughn and some true tempers.
as far as the manufacturers, i assume that barco holds the contract for now. generally, the USFS purchases mostly US made stuff, and again, i assume that is by mandate. then again, i have seen some Hyundai rigs toting the USFS shield on them as of late...
so basically, i don't know the answers to your questions. Moosecreektrails might know, however. i do know the answer to your last question, luckily!
as far as axe use goes-- yes! apart from the widespread use axes get as felling wedge pounding devices in the firefighting world, trail crews must use non motorized tools in the wilderness. My trail crew uses axes often to clear the trail, chopping thru logs <18" or so. too much bigger, and it is often time effective to get out the crosscut saw.
as far as the axes the various crew members used this year, (no photos, sorry) we have: 3.75# norlund single bit hoosier pattern, 3.5# kelly michigan double bit, 4# warren axe swamper, 4.75# collins legitimus jersey, this 6# chinese racing axe c*cksucker thing, 5# hytest trojan, and a couple 4lb kelly vulcan double bit, western pattern. honorable mention: a pulaski with the adze end ground off. it chopped like a sonofabitch until the user used it to chop an abandoned aluminum jetboat hull into scrap small enough to fit into his volvo beaterwagon.