Employer Contribution after Merger

Company A was bought out by Company B on April 1, 2018. Company A funded 3% SH and NCPS. The previous owners would like to fund the contributions for their compensation with company A from Jan 1 -  March 31 along with the participants of company A's plan too of course.

According to Co A, the acquisition was neither a asset or stock sale ?. They said " The entities are LLCs, therefore, the way the merger worked is that Company A contributed all of its assets and liabilities to Company B, and in return it received an ownership interest in Company B".

1. Sounds like an asset sale to me but i may be wrong. Has anyone heard of this?

2.  Does the safe harbor profit sharing have to be funded pre merger (1/1/2018 -3/31/2018) for Company A’s Plan? Can a discretionary new comparability profit sharing be contributed pre merger (1/1/2018 – 3/31/2018)for  Company A’s Plan? 

3. Is it considered a short plan year, does the ER contribution get pro-rated. I feel like this depends on whether it was a stock or assets sale.