There are tons of details you might want in a live launch list.
We suggest that you live launch the site and DO NOT promote the first day / until you know the site is ready.
Test all the parts, forms, everything for a few days.
Then have Google index the site. This will give you a high value jump start.
When you do live launch promote on all channels as aggressively as you can. Even some paid campaigns if that's in the cards for you.
The point is to trigger as much SEO as you can from the start.