My parent's place has increased in price dramatically.

Is there room to increase rents?

The law has kept those property taxes artificially low, regardless of how much their true real estate value increased over the past 10 years. 

That is still a win, and then assuming that over time the rents will increase, you will still be ahead.

Definitely consider things like your downpayment, avoiding PMI, and your current income or where it may increase too.

I would increase your CapEx and Maintenance.Do not forget to include Closing costs.

My tenant wants to move in his pregnant girlfriend, what is an acceptable additional amount to charge ? . I havent raised the rent in the almost 3 years he has lived there , he currently pays $1K/mo for a large studio...

I'm assessing another property and it doesn't appear to be as good of a deal ($80k $900/month) but in an area with exciting developments and higher potential for increase in value.

Yes as you are finding out a lot of insurance companies avoid student housing due to the increased risk.

I may be wrong, but determing the value of an asset based on comparable recent sales would give a comparable cap rate, but couldn't the value of a multifamily asset be altered through increasing NOI?