Apart broad's they don't recreate the province, like your mod, right?
1) Onra's creates all of the land in the province, but makes no cities, NPCs, etc. it is also stretched out to allow more play area.
2)Ali's then adds Elinhir on top of Onra's.
3) Broad's, i don't know much about. He apparently wants to recreate all of Hammerfell, but he was also talking about doing Skyrim and Summurset isles, if i remember correctly.
4) http://www.tesnexus.com/downloads/file.php?id=18715 is mostly player housing, and not lore friendly in any sense of the word.
3 almost certainly conflicts with 1 due to difference in scale. 2 and 3 conflict for the same reason, though i imagine an extensive patch could fix the issues. 4 conflicts with 1 and 3, but should again theoretically be compatible with 2 in the presence of an extensive patch.
our mod ought to be compatible with all of them, though it will probably need a patch for 3 and maybe 4, since we do add border forts to allow access to the new worldspace.