Maidhc O Casain
Na Bith Mo Riocht Tá!
Yes to the spell and kit (once you qualify for the spell, and if you find the kit as loot or for purchase, of course). I've pretty well opened up any official Paizo source.
If you're talking about just a regular old cloth kilt, sure! No mechanical change there so no problem.
If you're talking about just a regular old cloth kilt, sure! No mechanical change there so no problem.