signal path for two sources and my future boomerang III

[Rusty Perez <rustys.lists@gmail.com>]

Hi folks,
I'm preparing for a future purchase of a boomerang.
currently I only run my guitar through my looper,  but I want to run
at least one more source through the looper.

Here's my mixing setup.

vocals, guitar, and percussion in to three chanels of my Yamaha
StagePass system.
The stagePass mixer has 7 ins, 4 mono xlr-1/4 chanels, and 3 stereo
chanels. There is no effects loop, or monitor sends.

I'd like to run at least two sources through the boomerang, my guitar
and percussion.
I have two thoughts. Some sort of splitter for guitar and percussion
sending one in to the looper, and one in to a chanel of the mixer.
then the output of the looper would go in to a free chanel on the
mixer, but not pass live audio through the output, only looped audio.
but, what kind of equipment can I use to split my guitar signal
properly, and a mic signal properly?

Is this making any sense at all?

Or I could run my two sources in to left and right of the rang, and
out to the mixer, almost effectively having a separate looper for each
instrument. but then levels concern me because a mic will have
different levels than my guitar preamp, and I don't think the rang can
have separate levels for left and right.

Also, another thought is to use a small mixer, tiny mixer, all sources
in to the rang, then one source, maybe stereo, out to the mixer.

any thoughts? Anyone using two or more sources through the rang and
have some light to shed?

thanks!

rusty