Chrom x Sumia Lissa x Lon'qu Maribelle x Ricken Miriel x Vaike
These are the only ones I like. Ricken rescued Maribelle and their both young. Lon'qui was Lissa's bodyguard, Chrom and Sumia obviously, and Miriel x Vaike because of their tutorial. I'd also consider Freddy x Lissa and Male MU x Lissa.