You can only use each category once.
You get a +1 init if at least one unit for every four has MHQ1+. You can't get a +2 from that, it's a single +1 that you either qualify for or don't.
To get a +2, you've have to get the +1 for 1/4 of units with MHQ1+, and then fulfill a different category for the second +1. Have a single unit with MHQ4+ or have 1/4 units with RCN. If you fulfill all three categories, you get a +3. But you have to fulfill all three (1/4 MHQ1+, unit with MHQ4+, 1/4 RCN). You can't double up on the same category.