Site Migration Question

[bedocoman]

Hi Guys,
I am preparing for a pretty standard site migration. Small business website moving to a new domain, new branding and new cms.
Pretty much a perfect storm.
Right now the new website is being designed and will need another month, however the client is pretty antsy to get her new brand out over the web. We cannot change the current site, which has the old branding.
She wants to start passing out business cards and hang banners with the new domain and brand. However, I don't want to be messing with any redirects and potentially screw up a clean migration from the old site to the new. To be specific, she wants to redirect the new domain to the current domain and then when the new site, flip the redirect. 
However, I'm a little apprehensive with that because a site migration from the current to the new is already so intricate, I don't want to leave any possibility of error. 
I'm trying to figure out the best solution, these are 2 options I am thinking of:

1. DO NOT market new domain. Reprint all Marketing material and wait until new domain is up and then start marketing it. (At cost to client)
2. Create a one pager on new domain saying the site is being built & have a No Follow link to the current site. No redirects added. Just the no follow link.

I'd like option 2 so that the client could start passing out material, but my number one concern is messing with any part of the migration. 
We are about to submit a sitemap index to Google Search Console for the current site, so we are just starting the site migration. 
What do you guys think?