I would list what things you NEED and what things you WANT
for instance:
a gigbag is not a safe as a HSC but if you are bringing a backup bass won't you need to buy 2 HSCs? not to mention depending on how shady the establishment is you may not want 2 separate HSC/gigbags
maybe another hearty gigbag and this?
http://accessories.musiciansfriend.com/product/SKB-SKB44RW-ATA-Electric-Bass-Roller-Case?sku=544564
is it a deal breaker for you gig? nah
is your current setup rig a dealbreaker? nope
you are looking pretty good at what you have
I am gonna go against the popular vote and say
sell both the Ibanez and Squier
buy a cheap used MIM P bass
buy a used SansAmp BDDI or any unit that offers a direct box function (I use a freakin
cheap guitar multi pedal for the compression and DI)
buy a decent gigbag or get 2 decent HSC ( I think Rondo sells fauz tweeds for like 55 bucks or something)
Ppl are gonna ask why buy another MIM and sell the Squier
I agree the newer Squiers are amazing and even the SX I owned was a tank of a bass
but if he is to have a backup a passive bass that is somewhat complimentary to the Jazz would be beneficial
not that an active bass is more prone to disaster
I have 2 actives and 1 passive currently and keep a slew of 9 volts in my gigbag
but better safe than sorry until you can afford perhaps a 3rd active bass?