Please correct me if I’m wrong, but it looks like Plesk on FreeBSD stores all of the user data in /usr/local/psa/blablabla instead of /home/blablabla? Isn’t that kind of strange since most systems are typically partitioned with /usr to be a local “applications” volume, whereas /home/ may be local, on a NAS, etc.?

you can partition a system however you want
and the user data doesn't have to go there, you can edit /etc/psa/psa.conf and change it

Do I have to make a seperate partition for /eyc/ or can I use/etc/?

:D

you can do it however you like, you just need to make sutre there is enough space in the areas they list.

frozen had a typo :P. Actually it's not just on FreeBSD, it's just the Standard version of PLESK. It's actually /etc/psa/psa.conf on our servers.

oops, lol, not enough starbucks that day, thanks for pointing that out. fixed*