We have a single HVAC system that heats/cools the entire home.

We have a somewhat specific wishlist for lending requirements and terms that I will highlight below.

I received a quote in Southern California, but it requires year-round accounting at over $6,000 per year.Would a general tax professional be sufficient, or would I risk missing out on significant savings?

Or is he requiring a down payment?  

A partnership vs. disregarded LLC warrants consideration- you face different reporting requirements, limitations, etc. 

Maybe accept their fee, but require a shorter listing agreement (3-6months) to see the results. 

Updates include a new septic system, wall-hung boiler with radiant heat, and a remodeled kitchen with new appliances and an island.

Has anyone dealt with a similar situation and still was able to pass the housing code enforcement inspection (1 / 2 required inspections)?

If the back of the sofa isn't comfortable, they might be able to work on that, but it will require taking the whole thing into the shop unless it has removable cushions there too. 

I recently completed one on a multifamily property and found it to be a cost-effective approach.That said, there are a couple of additional factors to consider beyond the code differences between a garage conversion and new construction:Coastal Overlay Zones – If your property is in a coastal overlay, building a ground-up ADU may require Coastal Commission review, which can add time and complexity to the process.