Red Triangle, Multiple Codes, Battery Fan not spinning P3000, P0A84, C1259, C1310, C2318

Please help! for the last few months I've had the Red Triangle and these codes. The little bit of help i have received so far leads me to believe the Hybrid Control ECU is failing and needs replaced. I really don't know and would LOVE some help on this!

If the Hybrid Control ECU needs replacing - i understand this is under the pax side dashboard, behind the airbag... how do i replace that?

I'm currently getting 40-43 mpg. Car has 166K miles, HV batteries were replaced at 111K. My Dr. Prius app seems to show healthy batteries, i think (not that i know what i'm looking at with that). I think the rest of the HV system components are original.

I got the codes from my Toyota Techstream (knockoff) device and associated software.

Hybrid Control P3000 Battery Control System
Engine and ECT (indicates 1 misfire in last 10 driving cycles)
HV Battery P0A84 Hybrid Battery Pack Cooling Fan 1 Control Circuit Low
(I had previously received code P0A82 Hybrid Battery Pack Cooling Fan 1 Performance / Stuck OFF)
ABS/VSC/TRAC C1259 HV System Regenerative Malfunction
ABS/VSC/TRAC C1310 HV System Malfunction
Transmission Control C2318 Low Voltage Error (Power Supply Malfunction)
Air Conditioner B1421 Solar Sensor Circuit (Passenger Side) - i think this is normal

 

I couldn't figure out how to edit my post. I wanted to clarify, i took apart the battery fan housing (intake starting on the pax side backseat, going behind the backseats), and investigated the HV battery fan. It doesn't spin on its own. When I spin it, it seems to move fine but it doesn't keep spinning when my fingers leave it. I replaced the fan with a used replacement - same exact behavior, unchanged. So I don't think it's that fan, leading me to believe it's the HV Control ECU (not to be confused with the main ECU or any other of the 15,000 ECUs in a prius). Thanks!