Re the mortgage interest deduction: it has been lowered from $1 million to $750,000. That's the amount of the mortgage loan, not the total cost of the home. Mercifully, it will not hurt affordability for most people who buy a home in the $400,000-$900,000 range -- and most properties in L.A. County are in that range -- so your MID is safe. What does it mean for sellers? Not much. Your pool of qualified buyers will not shrink for median-priced homes and townhomes/condos. And, if you are selling a very expensive property, your buyers are probably not as concerned as they already (presumably) have ample means to pay the mortgage and don't require a big yearly deduction.
Re the capital gains on home sales exclusion: This is unchanged. If you are a single person who has lived in your home two out of the last five years, you can still exclude up to $250,000 in profit from capital gains taxes. If you are married, you can exclude up to $500,000 in profit. For buyers, no concerns here.
Stay tuned, though. I have a feeling that the U.S. Congress is not done tinkering with this tax plan yet.