Yes, this is all possible.
To your first qustion, if i have understand you right, then you would like to have Ered Luin, Erebor and the Iron Hils as a own Faction. Yes, this is possible, but the Edain Team had made that on this way, because so you have to add only one KI . If you choose the other way, you had to add a KI for all three Factions and the Number of KIs you can add is limited, so this is the easier way and you can be sure, that every of this Faction have a KI otherwise it can be, that you have exeed the limit and so you are not able to add one more KI.
And to your secound question, yes, this is also possible, that you start in this mountain with dwarfes in the mod, this is a entry in the Map ini of all Maps, on which you start with the mountain(you don´t start in this mountain on all Maps only on this, which have the entry in the Map ini. If you open the "Edain_Maps.big and open the Map ini of a Map, which has the mountain, you only have to delete the entry which makes the mountain possible. If you dont know, which entry you have to delete you must ask a Mapper from the Edain Team like
http://forum.modding-union.com/index.php?action=profile;u=1328or
http://forum.modding-union.com/index.php?action=profile;u=5ask one of them with a PM which entry you have to delet. Then, after you deleted this one entry, save the changed Map ini, save it into a folder with the Name of the Map. Then copy the original Map, the MapStr and all other files of the original Map folder.
Save all this files in a new folder, then replace the Map ini with your changed Map ini, then copy your whoole folder with the changed Map ini and move it to:
C/User/You User Name/AppDAta/Roaming/My Battle for Middelearth Rise of the witchking files/Maps
then start the Game, go to the Skirmish mode and klick the hammer in the top left corner at the list with the maps, then start your Map, one thing on which you can see, that it is your changed map is, that your Map has the hammer symbol on the place, where other Maps have a little star.
I hope, my english was good enough to help you.