Tenant occupied duplex to HH: should I require holdbacks or empty unit

[Annmarie Hill]

So a follow up to my prior question after speaking to an attorney in WA state: 

I am considering an offer on my first investment property to househack. It's a duplex with one unit vacant. The tenants have been served the 90 day notice to sell (Jan 1) required in WA state. One tenant is already vacating Feb 8. The other has not said a word so Im assuming theyll ride the 90 days out, or even not leave. Would you recommend making the sale contingent on the tenant leaving at the end of 90 days (or the seller getting tenant out sooner (eg cash for keys), and returning the unit broom ready, OR in the interest of moving forward would you negotiate a holdback in case eviction is necessary and to cover paint, repairs from wear and tear and carpet replacement, cleaning etc? Can lost rental revenue be included (so if it takes 3-6 months to evict can that be the sellers obligation through the holdback)? Would 10% of the purchase price be fair if I feel that will cover expenses (485K purchase price asking)?

My thought was to offer two different PP: maybe 10K more if they get the tenant out within 30 days, 10K less if we have to ride out the 90 days (but then Id ask it be delivered broom ready).  The holdback account would be to pay costs to get tenant out, replace/clean etc. The 2 bedroom unit that is still occupied is the one I need to live in with my kiddo.