[DragonSubie7]

HoosierGuy

Since the lower hose is cold, it's most likely the thermostat and/or a bubble as water isn't going cycling through the radiator, which is a lot more likely why the overheat condition.
Water pump problems are typically when they leak, rather than not spin.
If the car is overheating, the problem isn't that the thermostat is open, it's that it doesn't open.
Just saw @donkpow post after mine. I'm with him. Burp first.

Subarus are notorious for requiring more burp attention than a newborn.
It can oftentimes take multiple lower hose squeezes on more than one occasion to get the air out of the system.
It's a job that is MUCH better off with a funnel like @Black21Limited suggested.
Any auto parts store will also stock them.

Subaru cars are also persnickety when it comes to thermostats and radiator caps.
Lots of people have had problems when using non-OEM for these.