Also if you have been in the two units for a while still refi up to an acceptable level if you want to get cash out, can lower your payment and extend the amort period.  

Repeat that no closing is taking place until/unless the house is vacant, suggest the seller finds a temporary housing for the tenant + if I need to extend a closing, the seller himself pays for the lock rate holding and also compensate my own tenant who is supposed to move in on November 16.

It just sounds like if you can’t do a dp + are counting on a HELOC you might get over extended, but also it wouldn’t take much to tweak this and be set up soon. 

That may determine whether the offer will be written by you on State forms or if it will be written by the rep on a different contract. a builder’s contract may have terms about the appraisal where a low appraisal requires the buyer to bring any amount differential to the table at closing, especially if there are a lot of upgrades over base materials.Builders rarely negotiate on price but you may be able to negotiate some upgrades for your buyers, like quality of appliances, garage door openers, fixtures.If the project isn’t completed, your buyer ‘may’ be allowed to make some choices in materials, upgrades and cosmetic options.I would arrange a few walkthroughs to observe the progress before completion, with the buyers.Delays in construction and State required inspections, certificate of occupancy and cost of materials can complicate closing, such as a builder changing the price or the buyer’s rate lock running out of time and what it costs the buyers to extend it.Still recommend inspections to your buyers as new construction doesn’t guarantee things are in perfect condition, although builders typically have a window of time whereby they will correct what’s found by the new owners after closing, as well as some guarantees over time.Some builders have preferred lenders and Title companies - although the buyers don’t have to use them, they typically make for a smoother transaction and may provide discounts.If your buyers are loyal, and they happen to speak with a builder or builder rep without you, hopefully they won’t take the bait if the rep says they’ll get a deal if they leave you out.

Now that I’m interested, unexpectedly my extended family has decided to sell their largest real estate holding: a 6 bedroom 4 bath, 3 story home in the Pacific Heights neighborhood of SF.

@Steven Muresan I've never heard of charging tenants a fee when renewing or extending a lease.

For years, my one bedroom unit did very well on VRBO but once their family / extended family marketing strategy began to kick in, the viewings, inquiries and bookings for this unit took a dive, almost overnight.

Are you saying it could be smart to just extend current lease structure until the spring? 

Ideally, I'd like to have enough to cover an insurance claim and a few thousand extra for turn-over, cap-ex or extended vacancy.

The important thing is to not let these frustrations discourage you from buying a home; in the long run things tends to work out if you don't over-extend yourself and keep a level head.