MEP - waiver of eligibility requirements when joining

This is the first time since we've been doing this MEP that a new company is joining mid-year.

MEP has the same eligibility for all member companies: immediate for deferrals, YOS/semi for SH/PS (I know - I've tried to get them to change).

New member company (company just created last week) is joining effective 6/1/24.  We expect them to be top heavy, so all those non-keys active on 12/31/24 will get 3% for TH minimum even though they are not eligible for any employer contributions... well, now that it's 2024, we can actually not do that per SECURE 2.0 (all employees will be otherwise excludable for 2024 since they were all hired in 2024).

But they want to be able to give the participants (including themselves) profit sharing for 2024.  As long as it is stated in the plan document and/or adopting resolution, is it OK to waive the eligibility requirements for anyone employed on 6/1/24?

Bonus question: since there is no short plan year, there would be no pro rating the limits for 2024 for this member company, right?

Thanks.