New Battery? Monsoon Flooding? Help appreciated.

Hello!

Prius 2014 C, 170,000 miles.
Four days ago the blessed "pull over immediately, check hybrid system" warning came up.
Took vehicle to shop (towed) and received invoice with error codes a few hours ago:

P0A80, Replace Hybrid Battery Pack
P3000, Battery Control System
C1259, HV/EVControl System Regeneration Malfunction
C1310, HV/EVControl System Malfunction
C1464, Right Front Speed Sensor Circuit
C1464, Left Front Speed Sensor Circuit

I was quoted at $3,700 to replace the hybrid battery, $600 to replace the rear shocks, and $300 for Spark Plug replacement.

Questions:

1) Worthwhile to replace hybrid battery in a 2014 C with 170k miles?
2) $3,700 a reasonable quote to replace?
3) Perhaps random: flash floods have left my Prius in standing water right up to bottom of the doors for about 1-2 hours the past few months. Could these codes be influenced by that? Is 170K around the time hybrid batteries need replacement?
4) Other thoughts?

Thank you!
~Ilan