Hello Fellows!!

I'm originally from Brazil, i'm a commercial pilot with 1500 hrs (556 hrs in SEL and MEL pistons as Student + CFII and 944 hrs in B733 as first officer) and came last year to the U.S as a student M-1 to learn to fly helicopters. From FAA i have Private fixed-wing based on my foreign license and also i have Private, instrument and Commercial Rotorcraft. My life has changed a lot so today i'm legal to work in the U.S and i want to work on my FAA fixed-wing commercial license to apply for a job on the Airline. I have all the requirements to get a commercial license, just need to do the 3 hrs test prep to do the checkride but i'm having some questions and i hope some of you can help me.
First question - Do i need to have Commercial Single-engine and Multi-engine or just Commercial multi-engine to get a job in an airline? I know this may sound stupid but nobody at the flight school had an answer and this can save me a little of money.
Second Question - In the last 6 months i just flew helicopters and my last flight in B733 was in November of 2012, in relation of currency, is this a problem to the airline?
Third Question - With all been said...What would be the right way for me? Regional or Major?