M1A2C is ECP1A/SEPv3, M1A2D is ECP1B/SEPv4.
AMP is a separate program for M1147 HEMP round, and that data link can be used by variety of rounds, like M829A4, M1147 HEMP, I even heard about M242 HEMP which seems to be a US designation for DM11 that is used by USMC.
Oh and by the way, these is no such thing as SEP CEEP v2. It was always, only M1A2SEPv2, CEEP was a codename for electronics upgrade. But vehicle itself was only M1A2SEPv2.
SB Pro PE M1A2SEP is M1A2SEPv2 but early production variant without M153 CROWS-2 RWS and with few other differences. And as far as I know, SB Pro PE M1A2SEPv2 is not 100% accurate to the real thing, it lacks a lot of things considering FCS and other details. If it would be modeled as the real thing is in real world, then other vehicles would look even more primitive to it than they are now in SB.