The vesting for the property will necessarily be similar to that on the loan.
Whether you are listed as JT, or TIC, or CP will be largely irrelevant as long as the names on the property match those on the loan.
If you are most of the way through the loan process as John Smith and change it to John and Jane Smith, you may slow down the lending and the escrow.
Conceivably that could cost you the purchase or the deposit. Your results may vary. One reason a good buyer’s agent is a good idea.
An alternative solution is to change the vesting following the closing.
Recently, I had the experience of a client who was buying a short sale.
She advised me after we had short sale approval that she wanted to vest it in her trust.
In a normal purchase, this would be easy.
We would just have an addendum to the contract.
However, in a short sale, no changes are generally allowed during the contract period.
The solution was to send me down to the recorder’s office with a deed from the buyer to her trust the day after the closing.
It cost me 17 bucks.
I would caution you to check with your title company first to verify that the type of change that you want to do is covered by the title policy.
You also may wish to review the lender’s rules on this as well.
If the option to change vesting prior to close is available, that is generally better.