before I make the plunge... should this work?

I have searched through the forums quite a bit and saw conflicting things so Im just going to tell you my setup. Please let me know if you think I can do this easily or may have issues with latency, locking up, or anything else.

Equipment:

- MacBook Air 13" with 256GB SSD and 4GB ram. OSX 10.8.2. Runs perfect

- 2 acoustic guitars

- 2 vocals

- 1 Keyboard controller

I want to gig LIVE and be able to run everything through the mac. Ill purchase a nice audio interface to go along... I have a few in mind and will be USB since I need the Thunderbolt free for a 2nd monitor...

I want to be able to:

- Use keyboard controller to play piano, etc

- Have backing tracks live

- Have effects on both vocals

- Effects on both acoustics.

- Send additional click track or vocal que to headphones through a 3rd audio out port (not worried about this, its a no brainer)

Im also going to have a 2nd monitor setup through thunderbolt/HDMI to display lyrics. Im not worried about that.

This is a mid 2012 newer MacBook Air. This seems like a very basic setup but do you think it should all work toegther seamelessly? Im mostly worried about taxing the CPU and latency issues.

We're just doing a 2 man live gig at bars and restaurants. Nothing fancy. Were just trying to find the simplest and easiest way to do it with fast setup and teardown. Also going to get something like the Fishman or Bose L1 just to make life easier with the PA.

My guess is if the MacBook Air with Logic can do over 100 tracks no problem something like this should be nothing for it.

Please let me know what you think and share any advice. If this is cake, I may add more complexities into the mix but this is the minimum I am looking for right now.