SB-9: Will lender call note due?

[Wesley Yu]

This is a topic I've been wondering about recently:

Suppose I buy a house in California with conventional financing and subdivide it via SB9. If I sell the newly created APN, would the lender call the original note due? 

For example, suppose I buy a house for $1.5M, put down 20%, loan amount is $1.2M. I subdivide and sell the back lot for $700K. Would the bank that lent me the $1.2M say the note is due? 

Also, for taxes, what happens with capital gains in this situation: what is the cost basis I would need to record for the $700K sale and how would anyone go about proving that that is the correct cost basis? Because if it were owner occupied as primary residence  (and required due to SB9 wouldn't the second lot also be considered part of my primary residence thus I would be exempt from $500K capital gains if I'm married?) Thank you everyone.