1. Yes it will Luv. Estrogen is what's needed to grow your lining so as soon as you start taking the P4 that's that.
2. You wouldn't be changing anything, just increasing your dose of estrogen to help your lining grow a bit more between now and Thurs (I'd do an extra patch too for good measure!!). Increasing the estrogen isn't going to mess with anything as you're only using it to grow the lining which, once progesterone is started, will stop.
3. NFI Luv r.e BT's and not applicable when doing a FET r.e E2 levels. It's about the lining measurement.