I don't think so, Bri, because for 401(a)(4) you aggregate plans of the employer, including a controlled or affiliated service group employer. You also aggregate, of course, DC plans of an employer or controlled or affiliated service group employer for 415, but Treas. Reg. 1.415(f)-1(f)(1) has a special rule for 403(b) that treats the participant owner of the 403(b) contract as the employer with respect to it, but that is only for 415.
Probably yes, as long as it is prudent to provide the hard copy enrollment kits, and the cost is reasonable.
See fact pattern #5 here for a similar example: https://www.dol.gov/agencies/ebsa/employers-and-advisers/guidance/advisory-opinions/guidance-on-settlor-v-plan-expenses
If it is "totally separate" - how could he shift earnings? Based purely on the limited information provided, I'd say no. But maybe there is more detailed information on the facts and circumstances that might change this - for example, if he could have some of the patients come to him in his LLC, without creating an Affiliated Services Group.
No
This is also not correct
The maximum deduction is equal to the greatest of:
The minimum required contribution under section 430,
Funding Target + Target Normal Cost + Cushion Amount - Assets, or
If the plan is not subject to section 430(i), Funding Target determined as if the plan were subject to 430(i) + Target Normal Cost determined as if the plan were subject to 430(i) - Assets
The cushion amount is equal to:
50% of the funding target, plus
If plan benefits are based on compensation, the amount that the funding target would increase if future compensation increases were taken into account
If plan benefits are not based on compensation, the amount that the funding target would increase if expected benefit increases for succeeding years were taken into account, based on the average annual benefit increase over the last 6 years