That is not a fruit bearing tree, well, kinda, but not edible fruit. Just a ornamental. Winter is a good time to prune almost all trees, I remember that there is a pine in SoCal that ya couldn't. Canary? Jeffery? Other than that one, I don't know of another that would be bad to prune in winter.
To the OP, all ornamental Pears are notorious for bad structure, to top them would only make them much much worse. Real bad with included bark. If u are doing reduction cuts, do it back to something that is at least 1/3rd the dia of what you are taking and make sure that it has a good attachment. They will explode with epicormic shoots (suckers) next year, just FYI, if ya let them go for a couple years, you will have a big mess. High maintenance tree if you want to keep them small and from splitting. With them being so bad with the included bark, chances are they will split anyways. As they grow, they push on each other constantly and will eventually push on off. No matter what is going on above, 2 things trying to occupy one space. Don't try and fix all that at the crotch, where they all come out. Its too late and you will do more harm than good. That should have been done when they where bebe's. If they provide shade, and they are that big and old. I would start something else to replace. Just not another Pear. Maples are good, quick growing shade tree's, but stay away from the crazy hybrids they keep coming out with, like the Morning Glory Super Blaze Fire Crimson Blast. They also have bad structure. I have seen a few that where taken care of from the begining. They can be decent trees if maintained, but most are shoved in a hole and forgot about, till they get to big, by then, they are a mess.
