|Poor Wandering One|
My 2cp on witches based on playing one for 5 levels so it may only be worth 1cp.
Witches lack most of the classic sorcerer/wizard defenses.
Mirror Image, nope.
They get Symbol of Mirroring though for reasons I cannot comprehend.
Protection from arrows, nope.
Protection from Alignment, nope.
Resist Energy, nope.
Basically Witches are glass cannons. If it is not immune to Mind -affecting magic the Witch has a chance. Otherwise cast Mount and run.
Witches need to focus on things like initiative, combat casting and toughness because their nonexistent defenses mean they WILL get hurt.
Be wary of the Flight hex. W/O invisibility/Protection from arrows you just made yourself a pincushion unless you can zip from cover to cover.
Mind you grapple w/hair then half move straight up next round, repeat until they break free, is a fun tactic vs low cmb foes.
Abuse potions. Reduce Person, Mage Armor, Invisibility, Disguise self, these are your friends. Since there is another witch in the party look hard at the cauldron and coven hexes.
Fortune and Cackle. The meatshields will love you. Evil eye/Misfortune/Ill omen spell will help you save or die spells/hexes to land. You will want accursed hex and split hex when you can get them.
Get a lesser rod of reach if you are considering retraining the hair hex. You need a way to safely deliver touch spells.
Beg your GM to allow you access to the Web Bolt spell. I think it is the only low level Save or loose spell that targets Ref saves on your list.
Summon Swarm and Vomit swarm have subtle but important differences both will block charges though.