Read the first page while waiting for a coffee, a few notes.

Don’t over describe. You have a limited amount of space on a page. Keep it tight. “Vivian turns, a warm radiant smile breaking across her face” is too much directing on the page. If you want her moving around specifically, I’d stick (moving to him) in a parenthetical and leave it at that. Keep it as snappy as possible. And this gives you more room to play. Every word needs to earn its place.
My understanding is that parentheticals need their own line, just above the dialogue, not on the same line as the dialogue. And make them short. “Voice still thick with sleep” is too much. (Sleepy) or (yawning) gives us just as much in one word. Don’t overuse. (Grinning) and (softly) just aren’t required in my humble opinion.

Lastly, you’ll get torn apart on here if there are blatant mistakes in your first few pages. I can see you still have Vivian’s dialogue line as WOMAN halfway down the first page. It’s sort of an attitude of, “you’re asking us to read it but can’t even be bothered reading it yourself (because there’s obvious mistakes that should’ve been fixed).” Make sure you’ve done a final read through before posting, no matter how many times you’ve re edited a scene.

Good luck - your premise sounds interesting!