I agree with your comment about eliana being a great tank so you should use her as infantry, but who do you pair her with when nika is also peacekeeping and you can user her instead? pair them together?
If you have Nika to a decent place (at least 5111 id say) then for sure use her, thats a great pair, or alternatively, you could also run Eliana with any other unit type, or as a secondary, and have Nika lead your infantry
For the gatherers xp, for some reason my secondary hero doesn’t get any at all. I’m still kinda low level but my gatherers can earn like 7k exp per run, but my secondary doesn’t get anything and I don’t understand why
well you can prioritize on leveling up the skills of 1 hero at a time, but you will be able to bring 5 marches with heroes that are like 5-1-1-1 without too much problem
Garwood will be good for a tank march but most likely best to wait until you have 5 points in his first skill. Eliana can be paired with anyone really as a secondary, usually I would use her with infantry and using Nika or Bakhar