If you are not living in it you can't use the first time home buyer's option.
Here is a link https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/rrsps-related-plans/what-home-buyers-plan/participate-home-buyers-plan.html
Also, if you or your common law spouse live in a home that you, or she, own you can't use this benefit either.
All in all this seems like a ridiculous scheme that relies on potential tax fraud and overly complex decisions.
First step... decide what you're going to do with the house. There is no logical reason to leave a house empty for 2 years. The risks and costs almost assuredly outweigh the potential tax savings.
If you buy, why wouldn't you just get a mortgage and continue to invest the rest? With rates down around 1.65 it is kind of a no brainer. Why bother taking the extra step of transferring your savings into cash to buy the house and then applying for a HELOC?