Purchasing a duplex with a tenant already housed

[Alexander Johnson]

I am about to purchase a duplex that already has a tenant in one of the units while I house hack it. Their lease expires in July 2021.

What questions should I no doubt ask the current landlord? 

How would I handle a lease for that tenant? Do I wait to give them a lease with my terms until their current lease ends July 2021?

Should I increase rent to market around the area whether or not they're good tenants or not when their new lease starts? It's currently renting for $900, while market is looking around $1020.

If you know any tips or solutions for any of these questions it would be greatly appreciated to hear from the BP community! Thank you!