So I am planing on doing a hard mode run of Awakening with minimal DLC and grinding with no Frederick Emblem. I plan to use the following pairs:
Chrom x Robin
Lissa x Libra
Maribelle x Virion
Cordelia x Ricken
Sumia x Henry
Robin!Lucina x Brady
Chrom!Morgan x Henry!Cynthia
Libra!Owain x Ricken!Severa
Everyone else is optional but I'm thinking that it will be easier to manage with fewer units.