Evaluating the value of a multi-family

[Ryan Van Fleet]

I've stumble across a potential multi-family deal that needs some work. I'm trying to evaluate the ARV of the property and need some guidance. The property is a lot with 6 houses on it. It has septic issues, or lack there of. I'm thinking there is a potential to fix the septic and refi the property using the BRRRR strategy. This issue is finding comps.

Is it reasonable to find houses similar to what is on the property and add their values. For example the property has the following a three bedroom two bath, 2 x two bedroom 1 baths, and 3 x 1 bedrooms 1 baths. If I found similar houses in the area is it reasonable to add those values to get an estimate of the ARV, everything else being comparable?