FYI: The dealer is telling you to replace the MCM due to the P1644 code... because the service manual says a broken MCM will cause P1644. However, as others have stated above, it's almost certainly not the MCM that's actually broken.
You need to blink out your sub-codes to get more info... several of the P-codes you listed have multiple root causes. To blink out, you need to do one of the following:
-use the Honda OBDII tool, or;
-ground the SCS pin on your OBDII connector, or;
's OBDIIC&C tool.
Doing the above will cause your IMA light to blink specific codes... which will give us more info on what's going wrong in IMA-land. Based on the P-codes you provided, I would guess your pack is really unbalanced, and also you have corrosion on the two connectors between the seats (behind the middle mat, which connect the floor wire harness to the IMA wire harness). It could also be bad ground straps. But it (almost certainly) isn't the MCM, the BCM, or the ECM. Those things just don't break. Honda loves to replace them, though.