Hopefully, I-485
Ideally, yes, she'd maintain H-1B status all the way through the process, until she receives green card through marriage to you. For that she can find another H-1B employer who will "transfer" her H-1B. She wouldn't need to go through lottery or leave the country to do this. Why would it be beneficial to maintain status? So she could fall back on her H-1B status if marriage based green card does not work out.
This is the ideal scenario.... However, she has EAD and is married to US citizen. So she can switch to any employer she wants today. The worst case scenario, even if somehow I-485 gets denied due to technicality (forgot to submit evidence etc), she could refile I-485. Most marriage based GCs are approved unless she's inadmissable due to crime, fraud or misrepresentation etc.