Correction of SIMPLE After Crossing the 100-Employee Threshold

I have client who started SIMPLE with less than 100 employees.  They have grown over the years and have exceeded the 100-employee threshold for a few years (beyond grace period).  I see the IRS permits "correction" of this issue via EPCRS VCP -- 

https://www.irs.gov/retirement-plans/simple-ira-plan-fix-it-guide-you-have-more-than-100-employees-who-earned-5000-or-more-in-compensation-for-the-prior-year

by stopping all contributions to the SIMPLE and making the required VCP filing and sinning no more.

Question:  If we make this correction now per VCP, can the client start a new 401(k) Plan to permit contributions for the remainder of 2021?  There does not seem to be any discussion in the EPCRS corrections literature regarding possible establishment of new plan going forward.  For a bit of a wrinkle on this, what if the company is being acquired and buyer sponsors an existing 401(k) Plan and demands the SIMPLE be terminated prior to closing.  Can seller's employees participate in buyer's 401(k) post-closing in 2021?

Thanks