Transfer Cloudflare domain - downtime and payment

I am working to change my hosting account as I do not know the email associated with my original account and reset emails aren’t coming to anyone at my domain. I can update my nameservers with my registrar no problem and am prepared to do so.
I am wondering:

  1. will my site experience downtime with the migration, and
  2. if my other, lost Cloudflare account is on a paid plan, how it works transferring to my currently free plan. Will I have a grace period where I can pay the appropriate amount?
    I have followed this so far
    Move a domain between Cloudflare accounts · Cloudflare Fundamentals docs

Can you create an Account ticket and share your ticket number here? You can open an Account ticket here, https://dash.cloudflare.com/?to=/:account/support. Use the account you are using here, reference the email for the other account and the associated email.