Question - two partners own an LLP - 51 & 49 % respectively. They are a law firm. Neither reported earned income from the LLP - but they both both have their own individual P.A. -

Should the 401(k) plan be set up under the LLP name but have each individual partner's P.A. adopt the plan? Would that qualify as an ASG?

Any help would be appreciated.

Sure sounds like the classic affiliated service group to me. Are there other employee? A plan must be adopted by the employer, so you might end up with one plan and 3 employers adopting. See 414(m) of the Code and the related regulations.