Based upon your timeline I would apply to all of them and then decide about a month prior. Much can happen over the next year or so. I would also add ExpressJet with their IAH base for that reason. Right now it's a dumpster fire, but a new TA was just approved by the MEC and supposedly 25 E-175's are on the way, so you never know. Three years ago Republic was parking E-145's, being sued by Delta and going through bankruptcy. Look at them now.