Lots Of Midi And A Little Audio Options

[nyc_joe]

Hello, I want an environment where the midi tracks remain live once I am working with audio. The situation I want is to have a bunch of midi instruments playing that I can tweak while some vocal tracks are playing. I don't want to save the midi tracks as audio and export them into my mixing environment. Can this happen in Logic for instance. Does Logic come with a drum machine? I see the synths on the their website but no drum machine. I love Reason, it's so fun, but don't like the idea that I would need to bring it in as audio or do I?
And lastly, as an aside: is there a group of software that would allow one to record a sung melody, save it as midi and then use that midi track to drive synthetic instruments? Thanx again. Joe.