Offer Negotiation Stalled - Any Creative Ideas?

[Travis Moe]

I'm negotiating with seller on a 3/1 SFR with a 1/1 apt over the detached garage. Seller is willing to come down to a price point that works for me and my numbers - but the place is occupied. The 1/1 apt is fairly close to market rent with a lease until July 2019, but the main house is at around half market rent with a lease in place until August 2019.

This will cause negative cash flow during the acquisition and postpone the rehab phase for up to 9 months. 

The numbers kind of hinge on me being able to get the place reconditioned quickly. Otherwise, it seems to be a deal. I've asked for a price reduction to account for the low rent. Seller isn't keen to do that. 

Anyone have any more creative ideas on what I can offer the seller to make this work while accounting for the current leases?

Thanks!