Emu XL-7 & MP-7 User's Group

I do extensive arranging and some pc-based recording to share 
arrangements and new pieces with my groups. Many of the "groove" 
boxes I 've test driven seem more DJ oriented. I'm hoping this is a 
little different. I have 3 questions that need answered before I pick 
this up and become a contributing member to this forum!

1. My chord voicings often carry alternate bass notes and jazz 
groupings. Can I use the XL-7 to actually write, arrange, and perform 
songs along with a midi controller? Ease of use in that regard? My 
chord voicings often carry alternate bass notes and jazz groupings.

2. Any best practices ideas out there for sequencing entire songs or 
sets? Is the onboard card in the XL-7 enough for standard pop-rock?

3. Hypothetical situation: New progression gets thrown out at 
rehearsal, we want to jam on it and explore harmonies, etc... Can I 
use this box on the fly to give us a foundation?

Any other thoughts you can offer? Thank you for your time, I'm 
looking forward to more discussion with you all.