Multiple faults with traverse

Good afternoon about two weeks ago I started
to get battery charging system fault. I checked
the battery voltage and it read 11.9 and started
my vehicle up and the voltage dropped to 11.5. I
changed the alternator and the jumped my
vehicle but the jump did nothing. I then changed
the battery and went to push the start button
but did not have my key fob so when I opened
the door the alarm went off for about 5mins
and stopped without me hitting the key fob. I
went to back into the vehicle with the key fob
this time and the vehicle will not start at all. I
put the key fob in the transponder pocket and
now multiple faults  show up alarm deferrent
system, no front or back camera fault. I
disconnected the negative terminal post for the
battery for 10mins and when I reconnected the
terminal the faults were still there? What do I fo
next ??