we have done something similar before, at summer camp. . .As a thought if you have a number of your power boxes you don't need to have all the power in one place and distribute it at 12v the way you do 240v, you can have small zones around a power box.
That may make more efficient use of the stored charge.
This is the way I run the event PA, each amp point has an 18l Really Useful Box with 40Ah or so of SLA in on Andersons
the main van + Tent was setup with.
twin 100ah battery boxes, 400w solar and the Anker 757.
.
we had some interesting Inverter efficientcy numbers to tried some smaller mini inverters. . . like the cracking little 300w Bestek.
.
then we had the DiscoTent powered off another two battery boxes. .
and another 400w solar
and a EF River Pro for mains. . .
.
we was running 1000w JBL PRX PA speaker up,
with some LED DMX lights,
and a couple of MINI Moving heads,
plus the love island style lights.
and, and , and , and. . . . . . . .
.
..
even with all this, we still had to use the vans dc-dc charger to try and recharge some of the boxes. . . during the day.
....
even with 800w solar,
and 600ah lithium . .
we still run out of power. . . . .LOL.