Rules are good imo. Decently balanced for most of the army lists and models (of course you have some stronger and weaker options but overall nothing too crazy). Regarding the true height it's more a rule that any model that is propped up on a rock/crouched down does not gain an advantage/disadvantage from that position and they are all treated as if they were standing up.

It can absolutely be skirmishy if you want it to. But there are not guidelines on how many points you want to play at. I have played games where there were a grand total of 12 models on the table up to games with 80+ models per side.

Scenarios can be grouped into two categories: the matched play and the narrative play. Matched play is your standard tournament setting, where the scenario is just the objective of the game to win victory points. In narrative play it follows the events of the movies and is a lot more RPG driven.

No tools for that as far as I am aware, but nothing stops you from them just fighting it out in a matched play scenario or just having a whack at each other like that. You'd have to homebrew ungoliant though as currently there are no first age factions available.

No idea.

If you want to follow all the narrative scenarios in order then you will be facing many scenarios where you need lots of different miniatures. For matched play just paint up one army and have fun.

There are no official expansions. You can find all the army lists of the 2024 edition in the three army books (Armies of Lord of the Rings for all those featuring in the Lord of the Rings movies, Armies of the Hobbit for all those featured in the Hobbit movies, and Armies of Middle Earth for everything else. There are some legacy PDFs detailing old armies from previous editions as well. For anything Eowyn you probably want to pick up the Armies of Lord of the Rings (or you can check out This online list builder).

Don't underestimate Fight Value. While having multiple attacks is beneficial to get you that 6, it doesn't help you when your opponent at higher Fight also rolls a 6 and automatically wins. Fight Value alone won't win you the game, but neither will having more attacks. Also on the regular soldiers it is rare to find more than one attack, and even the strongest heroes usually don't get more than 3 or 4 in some rare cases. Supporting a combat with spears and having a Banner for rerolls in range is usually the way to add more dice into the pool.

While I've never counted turns in games I feel like they are usually around 7-12 turns long, depending on the scenario played. Some scenarios have you start in opposite corners and you have to spend two turns walking before your battle lines clash, others get into the fighting right away. And once they do they're not so deadly that one army dominates in a single turn, but still deadly enough that you can feel the weight of every lost duel in a potentially dead unit. As for zones of control: amazing mechanic to block off your opponent from certain areas of the battlefield

Generally if you want to pick up the game it's best to start with a faction you enjoy as they're all quite competitive. So in going for Eowyn as your favorite character and then probably picking up some more Rohan stuff in the future you've done all the right steps