I have several of those books,
MechWarrior guide to solaris VII most of the traits and lifepaths are in ATOW or ATOW Campanion, it also has extensive reprints and conversions of mech scale combat (BMR/ Total warfare equivalent) into personal scale, a brief history of Solaris 7, and some info on running a campaign, along with an adventure (first impressions) and maps and location info.
MechWarrior guide to the clans has a bunch of information on setting up clan characters, some additional skills, and affiliations (in ATOW) information on clan lifestyles, and motivations, technology, campaigns and vendettas.
MechWarrior Lostech is mostly in ATOW it added additional traits (gear) like EI implants additional gear (most has equivalants IN atow or companion) and a bunch of Battle Armor stuff
classic battletech companion has lifepaths, and similar rpg stuff, affiliations, what looks like expanded battle armor construction rules, and some battlemech information (startup stuff, and buying, selling, and stealing battlemechs and vehicles)
guide to covert ops has some additional traits and implant information (most should be in atow companion) an adventure and information on running a covert ops campaign.