We'll, you've got yourself a good digital piano. Unlike Indigo, I don't like Yamaha piano sound. But in a church setting, the bright tone is quite helpful to cut through the mix especially since we usually play in a heavily echoey hall (bright sounds helps to give dinstinction).
So, you are set for piano and e-piano. You've also got organ which is some form of B3 although you won't be able to change the tone like having draw bars etc. And of course, playing hammond on weighted keys will be a challenge. But nevertheless, you've already got the bread-and-butter sounds.
The only shortcoming of the P200 is the balance of volume when you layer sounds. You probably already know and experienced this. When you play with the volume control in dual mode, the volume fades from one sound to the other. I don't like that. Sometimes, we don't want the volume of one instrument to fade off - we want it to remain at the same volume while the instrument no.2 crescendo to louder than instrument no. 1. This is not possible for the P200. When you move the volume pass the middle line, instrument 1 starts to fade off. The solution to this is, of course, a sound module. Then control the sound module's volume via an expression pedal.
I really wouldn't recommend anything too costly. Any second hand Roland modules will suffice your needs. JD990 is fine. If your church has the budget and the leadership agrees with upgrading, in the situation where there is only one keyboardist, I would suggest selling off everything (the Yahama and Korg). Then get an RD700SX - no need for any external modules. This is the best keyboard for live situations and gives you a lot of live control as the only keyboardist. Assigning zones and splitting the keyboard is very important for a 1-keyboardist situation.
Playing in church is very different from performing live. Hence the needs will be different. You will not need to have ultra-realistic sounds; lead instruments are not very important; in fact, the playing styles are vastly different. Some people may think it makes no diffference, but the skills-set needed to play in church is very different from live performance. The sounds and equipment needed are therefore, also quite different. The entire purpose is different. You can be an excellent live performer, but a terrible player in church. When playing in church, the keyboardist is aware of multiple things at the same time - other players, the worship leader, the people singing, the backup choir, the acoustics of the place (which is usually bad), and improvise according to different situations - all these things go on at the same time. I don't want to turn this thread into a church-keyboardist thread - but I'm happy to discuss things like this if you want to pm me - or start another thread so others can join in.
