I recently wrote this for a similar question. I forgot to mention she had an MC6 to change Scenes and the few IAs, so considering how Scenes work, yes it will “work.”
Here’s what I wrote:
i recently did a weekly gig where my duo partner and i shared the Axe3 for both of our guitars. my setup uses a guitar with electric pickups and a piezo/acoustic sound. so technically we had 3 guitars running through it.
it "worked" but with planning. tone wise, sound wise, and all that, it was great.
the issue comes down to changing sounds, especially when it comes to Scenes. to make it easy for my partner i just gave her 3 Scenes, with a few IA switches for delay, chorus, and a boost (filter block). if i'm on a clean sound, and she's on a lead sound, if i change Scenes so that i'm on a lead sound, her sound will change because a Scene currently can't "ignore" blocks. if she turned on the Chorus block with the IA, and i changed sounds, her Chorus block would turn off. so in short, any Scene change that one guitar needs will affect the sound of the other one.
so i split the "scenes" into 2 groups of 4 - up to 4 for me, up to 4 for her.
the rule was whoever is singing the song, they stay on their "clean" sound only. this allowed me to do this:
if i sing:
S5 - my clean, her clean
S6 - my clean, her clean lead
S7 - my clean, her distortion
S8 - my clean, her distortion lead
if she sings:
S1 - my clean, her clean
S2 - my clean lead, her clean
S3 - my distortion, her clean
S4 - my distortion lead, her clean
so while i sang, she could change Scenes all she wanted, but my clean was unaffected because none of "my blocks" changed at all. no gap or anything while i played and she changed Scenes. same for when she sang.
under all of this was my piezo/acoustic tone, where the 3 blocks used there never, ever change, so personally, i always have a fall back to change to the acoustic sound using a switch on the guitar itself. it helps in this situation too, where just in case some Scene was changed wrong, i have some sort of guitar sound (acoustic).
it's this sort of consideration that needs to be made when using multiple guitars with one Axe.
it would be great if the "Scenes can ignore blocks" wish can be implemented in the future, or other similar things. i think many people can't afford an axe per player, so they don't buy any, and FAS gets 0 sales. but if features that helped us "share the axe" with multiple players, many bands would get at least one. (how's that for marketing
)
the situation i described is a bit improvisational - we don't plan songs or rehearse. we just play and adapt. that's why having the singer stick to the clean tone and the other player improvise works out.
with fully planned songs, setlists, and tones, this might be a non-issue since every change can be known at all times. but you can't stray from that probably, unless you setup like i did or something similar.
so it can work. but you need to plan.
