Legal Question in Real Estate Law in California

No, unless you are trying to disrupt a contract between the owner and another buyer, but I'm hard pressed to think of what the point of making a proposal directly to the lender would be.

It's not against the law, but the lender isn't the seller, has nothing to sell, and for that reason is not in a position to accept an offer to buy. At most, the lender might give you an indication as to whether they will approve a sale at that level, but my belief is that the lender would tell you to deal with the owner/seller. After a foreclosure in which the lender is the high bidder, it's obviously a different matter.

I agree with the above responses, but point out that there is nothing illegal in you contacting the lender and mucking up the transaction.