@Heath Reid Assuming that AL laws are similar to MA, you'll have to honor existing leases.
One way around that is to offer cash for keys. Talk with the tenants and ask if they would be open to the idea. You pay moving expenses and pay them something for their troubles - maybe a month's rent in the new place.
Peace of mind and money.
Like the poster said above, make it effortless for them to relocate to a different place including a financial incentive.
That's the only way I would move from somewhere that I liked.
Hopefully they are month to month or near lease end. If so I would send them notice of a substantial rent increase and let them make the decision to move on their own.
Ask the seller about his lease - some people have a 30 day notice upon sale clause.