You can get all three secondary skills. ie you can have first aid, cooking and fishing all at the max. Definitely make sure to keep first aid maxed, other than that the other two are up to you to decide if you want to level them or not.
Well enchanting does make money if you intend on selling the materials you get out of disenchanting items. But first of all you will have to sacrifice some of your materials to skill up your enchanting so you can disenchant items and get materials actually worth something to sell on AH. Also low level enchants I would do for free to get your skill up until you reach lvl 100 when you do the occasional freebie. After then you should either charge for the enchant or let the people buy the materials off AH and let you do the enchant for free. Either way I think Enchanting is a pretty good profession - it costs a bit to start off with but it does reward you in many ways!