It's VERY common to see properties around here with undersized septics.

Was wondering if this is a common situation with underwriting VA cash-outs. 

And what could be some of the pitfalls?

Prices east of Worcester towards Boston have become untouchable for the "common folk," and first time homebuyers in the Metro-Boston area are being pushed as far west as Worcester.We made about 15 offers before we got a bite on a 4 bedroom, 2 bathroom, 1600 sqft home in the Webster Square area of Worcester.

It’s not common but it does happen.

Multis / rentals are not common, and in demand.

Any tips on finding properties, researching the market, areas to avoid, common rookie mistakes, ANYTHING!

You had a very common problem (I've had it too) and the best thing you can do is exactly what you did: get quotes and then get it repaired. 

In general I don't think they matter too much, however, against common wisdom, I had to change the name of the last cabin I purchased.  

@Gino GonzalesAcquisition fees are typical (1%-3%) with larger multifamily projects and very common with syndication deals.