thank you everyone for your input.
Scuba_Steve,
Would it be OK to use acryclic/plexi to make the overflow, or is glass a better option? How about for the sump/fuge baffles? Is it possible to fit a sump and fuge into a 20 gallon under the 90?
The cold water tap for my washer is a perfect spot, thank you!
Would it be advised to also set up a closed loop, or would a few powerheads suffice for flow? Man, that's another worry... how do I manage to balance out flow to prevent flooding our apt.? What about power outages, is there a way to setup an emergency switch / system to prevent floods during power outage? eek!
Again, thank you everyone for your help. I think that blanket of panic/impending doom is starting to subside.