ok, where shall i start
The environment question was more about your synths/mixers/external fx/...
The audio environment you described seems to be the simple logic standard audio mixer environment.
MY entire studio consists of a Roland JV 1080, an Akai S3200, a Behringer 16 track mixing desk and an Opcode Studio 4 midi interface. I use a Mac.
thats what i wanted to know

This is a perfect starting environment - you may buy a cheap Midi claviatur (Like
the Roland PC180 i think) and a pair of studio monitors and then it will be really nice...
Let's save the quest. I'm using a pc, but the way should be almost the same.
The windows you opened were quite right for what we want to do. The audio window can remain unchanged, the midi environment should be changed slightly.
Step by step:
1.) You have 2 multiinstruments in your real world, so we have to create 2 multiinstruments in your logic environment. That step has been done by your merchant it seems.
Please ensure, that the midi port & channels are set correctly selecting the multi's.
2.) Enable the Prg Vol and Pan Checkboxes at each channel of your Roland multiinstrument. Then fiddle around with the parameters - voila! You should see the result on your 1080.
The point is, that the whole environment its channel settings included is part of the current logic song - once you save now, you will get those parameters set when loading the song the next time.
+) You also can export an environment without the midi data and set this as start environment for logic, but thats a different story. (And makes no sense cause you want have so much songs that use exactly the same instrument settings

)
+) If you have to setup a instrument of your synths especially, you should do this via midi sysex on the first beat of each track. (I also do my prg-changes this way and EVER start my note-on's on beat 5, because so u also can take the midi only and go to a studio without logic)
3.) manipulate your sounds on your roland and store them ans 1080 user performance directly on your synth.
4.) not neccessary today, but if you want to connect other midi-hardware, you simply have to create other multi instruments.
This is the simple but nice way, but there is also the possibility to create an environment where you can visually control your 1080 and you 3200 completely, but thats what sounddiver is 4 - it is a collection of GREAT environments of 1000-s of synths, samplers,... (if u dont like the little knobs and the mickeymouse displays

) This also gives u the possibility to store your 'special program' as midi sysex in your logic environment.
ok, at last: you also can store your midi sysex like the program change at the first beat of each track, but u first have to get your program as midi-sysex. You can program the sounds on your roland an transfer those settings per midi-dump but that means frickling around for hours
i hope i've answered what u wanted to know and didn't tell u things you already knew for years...
greets,
mark