I also have a 99 FRC. If the utters are clean. There is another small hose for the AC to drain out. It’s on the passenger side, at the fire wall. Sometimes it will clog. It happened to mine and the water would leak in on the passenger side foot well.
Well . . . it sounds like you already know what to do! Just keep looking for things COMMON to both codes. Two or more failures simultaneously generally indicate a loss of power to a system. Especially the U1016 code that tells you the system lost its mind for a moment -- with the ignition on -- and started spitting out junk. And yes, the rough ride would bring out the worst in corroded connections. I would disconnect the negative battery and start cleaning up connections concentrating on the power connections, but it wouldn't hurt to unplug the modules and inspect and clean up their connectors. I would consider water damage to any control module as a last resort as most modules I have seen in modern cars are environmentally protected with sealed enclosures, conformal coatings on the boards or potting compound. It is usually the connectors that are vulnerable. As for the power window -- dude! they are designed to fail, but an open power or ground that is affecting the other components could cause that, too. My experience is that window motors have the shortest mean time between failure of any part on your car!
2K FRC.. i silicone sealed the gap that runs along the top of the doors, but still water gets in.. i keep it covered whenever it rains. Same prob with the doors.. those connectors are a pita to disconnect to clean.
