Still think that starting now from seed, Lisa will have very small plants by the end of summer even if all goes well. Lavender grows pretty slowly even at the best of times. They'll be awfully vulnerable to cold next winter.
She gains months, and possibly survival of the plants next winter if she starts with at least some transplants.
I think there's a lot better use to be made of all that space in your greenhouse. Grow some plants that are sure to germinate and mature before next year, Lisa!