First, only MAIS schools that are SACS accredited should be able to join. SACS accreditation is a basic merit of being a decent school. If you went to a school that is not on this list, then as an alum you need to get on their ass and tell them to put some more emphasis on education. Personally, I'd shut them all down, but just like Alabama, there is a market for true segregation academies/schools that don't care about academics at all (Starkville Christian).

Adams County Christian
Bayou Academy
Benton Academy
Brookhaven Academy
Canton Academy
Central Hinds Academy
Centreville Academy
Columbia Academy
Copiah Academy
Greenville Christian School
Hartfield Academy
Heritage Academy
Hillcrest Christian School
Immanuel Christian School
Indianola Academy
Jackson Academy
Jackson Prep
Kirk Academy
Lamar School
Lee Academy
Madison Ridge land Academy
Magnolia Heights School
Manchester Academy
Marshall Academy
Newton County Academy
Oak Hill Academy
Oxford University School
Parklane Academy
Pillow Academy
Porter's Chapel Academy
Presbyterian Christian School
Russell Christian Academy
Simpson County Academy
Starkville Academy
Sylva-Bay Academy
Tri-County Academy
Trinity Episcopal School
Tupelo Christian Prep School
Washington School
Wayne Academy
Wilkinson County Christian
Winston Academy

42 of the 97 MAIS schools are SACS accredited. My plan is to invite them to the MHSAA with an enrollment index of 1.2, which would put all but 14 schools in 1A and 2A.

3A schools: Heritage, Hillcrest, Indianola, Lamar, Lee, Magnolia Heights, Starkville
4A schools: Washington, Parklane, MRA, Pillow, Presbyterian Christian
5A schools: Jackson Prep, Jackson Academy

In 5A, Prep and JA would roll into the district with Ridgeland, Pearl and Germantown and fit right in football-wise.
In 4A, Washington and Pillow would go in Region 3, MRA in Region 6 (which they would dominate) Parklane in Region 7 (with McComb) and PCS in Region 8 with St. Stanislaus.
In 3A, Lee and Mag Heights to Region 2, Indianola to Region 3, Heritage and Starkville would go to Region 4, Lamar to Region 5, Hillcrest to Region 6 with St. Andrew's