I recently have put together a game of 5e Dnd for some friends and the idea is based around using fire emblem

Some mechanics we’ve decided on, all humans for race no stat benefit however, with a stat array of 16,16,14,12,10,8

Swords get an extra d8 damage against axe weilders, axes get an extra d8 against lance users, and lance user get an extra d8 towards swords users

All official 5e classes plus you will pick your fire emblem class and at each asi you will gain a feat related towards your fe class,

Bows get adv. plus 2d8 extra damage to flying mounted people,

My question is this, I’m struggling to write this campaign for them a bit, and was wondering if anyone wanted to help me write it ?