You write you also want drumloops-arpeggiation etc... so my guesses are you want in fact full orchestra accomp.
In that case your best solution would be an arranger keyboard..
Has everything you asked.
Easy to play for anybody if using the ready to go banks.
The only think lacking are programability of synth.sounds, but I doubt if your church needs surrealistic /space/house sounds..
For $ 2500,-- you are in the range of top pro arranger boards.
Model to look out for this moment;
Read thru the general arranger keyboard section of this bbs and you will find most answers you need.!
Keyboards/Sound Units: Kurzweil 2600S, Roland VR-760, Acces Virus C, Roland G-800, Akai AX60, Minimoog, Machine Drum, Roland R8-M, mediastation x-76