If they have been decent tenants, granted you are taking the word of the seller, I would prefer to keep a tenant in place especially if the will handle the rent raise. This keeps you from having to handle a turnover and wait on most of the renovations. If there is no formal lease they should be considered month to month and I believe they should be given 30 days notice to vacate/ non-renewal. So out by close isn't going to happen unless they leave on their own it will likely be the beginning of the next month depending on their lease. I would serve the eviction/ non-renewal in writing and verbally. I also keep a log of contact emails back and forth, texts or a phone call summary- date time and brief summary of conversation. That being said if they want to stay, I would vet them through your normal methods. I usually offer to pay for the check fee, for background to help make that a smooth process. Good luck and don't stress it too much it will be a short term challenge for your investing career!