up front cash for emergency roof fixes, etc.?

A fridge malfunction is an emergency because tenants can loose their food. 

I keep a cash cushion that (I think) is adequate for emergencies. 

If so, how do you manage maintenance or emergency issues if you are managing remotely?

She stated some family emergency and only gave me 3 days notice but only after I reached out right before her first payment was due. 

Keep your 50k for emergencies or repairs or even find another duplex/fourplex to buy with a conventional loan. 

Where are the emerging areas? 

There are a few KPI's that make IB an emerging market.

I have a HELOC that I use as my emergency fund / reserves.

You should also have roughly a 10-20% buffer saved up above your rehab budget for unforeseen repairs that might need to be taken care of or for emergencies like a pipe bursting or a break-in.Investing in real estate should be with your "play" money when you're just starting out, you don't want to be putting your entire savings into your first deal and have it go sideways and lose everything you've saved up.