ok soo...comming from someone who just started with them, and who taught herself makeup, i think i may be able to help
firstly, the requirements are what Aquilah said, you can't go there on just personality but personality is HUGE. They look for potential and if you know mac then you know customer service is a big part of the company. I initially thought that you had to be a seasoned ma to work there. But i taught myself everything i know (with alot of help from mut) and i was myself in the interviews and i got it.
For us in Montreal, you need to go through a group interview with about 8-10 others, (mac interviews everyone who hands in a CV/application, so your gurenteed an interview) secondly, if they like your personality, and they like what they see on your resume, they call you back for a makeup test. This is where the skill comes in, you need to know what youre doing, but you dont have to be perfect. Then if you make it, they will send your application to the store or counter that needs people and then you do the last interview with the manager there, if you fit for their team, you get the job
I would definitly NOT say its necessary to work there, but it Is super helpful, ive learnt soooo much in the past little while! But back to Aquilah, you don't have to go with MAC there are other wonderful companies ect...
SO apply, you have nothing to lose, but all i know is its a long process so if your mac's do it the way ours does, they wait untill they have alot of interviewees before starting, so don't get discouraged!!!!
HTH pm me if you have any questions!