Substitution of security trigger a new application?

The two properties we want to reconfigure into three to build in the middle are all x-coll with our PPOR. This has never been an issue for us but since joining the forum I understand this is the time to remedy this.

Our plan was to revalue all three properties, which should allow the bank to release the title to one of the properties that we hope to build behind.

However, I'd prefer to release both so that they are completely untied to any bank until absolutely necessary. We hope to build two, rent them out, get an asset lend on them, draw out the funds to build the second two. The new block is a combination of the back yards of the two currently mortgaged IPs.

Initially, we planned on applying to reconfigure the blocks and leave one house out of the proposed DA completely, but now it seems this house must be moved forward, hence my new idea to completely remove both houses from any mortgage.

My new idea is to substitute another unencumbered house to make up the shortfall that just our PPOR would pose.

I'd like not to have to submit any form of new application as we are "retired" and would have trouble getting a "new" loan through.

Is it likely a bank would accept one house for two and just change the house that the security is taken over? Could we do this with Westpac without having to go through a new loan application?

I'm assuming we would have to have PPOR plus newly proposed house to come in at under 80% to avoid LMI?
If the loan mount doesnt change UP, and the security LVR the loan ws initially approved at doesnt increase, WBC are pretty simple with Partial Discharges such as this.

There are lenders that would make you jump through hoops of fire to achieve the same once retired, which is why lender selection planning is super important beyond the acquisition phase.

for many, the most critical mortgage structure planning is AFTER we are "done" and are into consolidation/diversification