I think 20% is easily obtained with a decent credit score. 15% will be a little more difficult.

How difficult is it to obtain a second mortgage about 6 months after purchasing my first rental property?

This is difficult to do if any of the parties to the exchange realize tax benefits from the transaction.

Understand that it may be difficult for the tenants to find replacement housing, and especially with government subsidies playing a role, you may allow them a longer-than-average time to find new housing. 

Once you take out the HELOC, that goes against your equity on the property so a Cash out Refinance would be a little more difficult because you would have less equity.

I know how difficult it is to find good deals having 20 years of experience in development, appraisal, architecture. 

I'm concerned that because both tenants are long term they would be difficult to remove and I'd have to go through the eviction process. 

I agree with him, I think finding a legal, turnkey 3 family with parking under $400k is going to be very difficult. 

Its very difficult finding anyone that can do any kind of home maintenance , plumbers, electricians, contractors, etc...

That would be very difficult to track and get reliable data on.