Do cohorts start with their own magical gear based on level or no?
As someone said; yes, they do get own gear based on their level but you can invest own char money to upgrade them. You get 25% of your total wealth as extra to upgrade followers also (example give magical siege engines or give your elite guard +1 armor and weapons).
Oh, I should check this for approval.
Zaer, in 3.5 a blink dog was a valid Improved Familiar. Is that okay in this game? :)
I say.....yes. Although it's listed also as cohort but I am okay with blink dog familiar. Or other improved familiar variants in 3.5 (i do not remember anything broken and only real broken one was imp/quasit when starting go crazy with spells and items).
Can the landlord feat be taken multiple times by my char? In addition, may I have my cohort take the feat as well?
Answer to both questions; NO GOD! PLEASE NO!!! NOOOOOOOOOO
Actually if your replacing some Hathran things with hex interaction/progression I may go back to it. Witch + Hathran is very flavorful for for being a errie beautiful woman with dark faery magic. As long as I can utilize spells from things like the spell compendium. (For simplicity just say all sor/wiz spells from noin SRD 3.5 are witch spells seems best. You could say cleric or druid instead i suppose)
Well, as someone said I would allow the spells case by case basis to consider are they witch themed. As witch spells overall are meant for not blast things like wizard (it's not their stuff really). But they do have some other means of offense (strangling hair is damn fun to use and so is black tentacles). Mostly witches have debuffs, cripple and hindering spells.
But if you changed your concept I need check the PrC what you have now and see can I edit that. But first need do Hathran edit and see will it tempt you enter it as a witch.