This upload will allow compatibility for both addons. You can use all the buildings now provided by Balmora Expansion, with no doors blocked.
Fixes include:
Removing the landmass covering the top left of Balmora in the mountains.
Removing rocks blocking access to buildings
Allowing movement  on paths to certain buildings
Moving an npc home with doors that were not accessible.
Altered the river so the NPC's would not get stuck and drowned

***please note that version 1.0 has an alchemy merchant addon included, which was installed accidentally, otherwise, it seems to fully be working***
-I will attempt to add a version with the merchant removed in the next version. I am new to performing mod changes

To use this file, download rebirth first version 4.9 https://www.nexusmods.com/morrowind/mods/37795?tab=description.
Then download Balmora expansion https://www.nexusmods.com/morrowind/mods/44659?tab=description.
Once both are downloaded, install the data files as requested to the Morrowind folder.
Then you can activate the esp file in replacement for both esp files from the downloads.

Update-added fix patch for those who already have the files on the system. This also allows access to zins underground, if you have it installed, near the temple.
-I do not recommend version 1.0 of the patch, as I discovered some issues, which were not fixed. I will try to upload a newer version.

If you find any errors, let me know, so I can attempt to fix them.

Credits to johanrosen(uploader), Trancemaster_1988 (original author), Gorg CanadianIce Jeremy (authors) and DeinClickerMan(uploader)
Sorcha Ravenlock (author of the alchemy merchant)

Feel free to update any images, as the one provided is from the original version of the balmora expansion.