First to explain how flora texture replacers work.
Flora is in the following directories, packaged in the Skyrim - Textures.bsa:
Because Loose files take precedence over BSA's if a mod author uses these directories and puts replacement textures in them those textures will be used instead of the the ones in the bsa.
As far as Aspens in Yurt's mod is concerned he has them in the Textures\landscape\trees directory
If you were to delete these files Skyrim would go back to using the vanilla textures in the bsa ie the light orange ones.
If it was just the leaves you didn't like you could keep the 'treeaspenbarkcomp' files.
Similarly you will find in the plant directory 'THISTLE01.dds' if you delete this you will get the old thistle colour back.
Now if you wanted to keep Yurts Aspen textures for all the existing trees but wanted meshes available that used the vanilla skyrim textures it is a rather more involved and tedious process because Trees and stuff can't use CK Texture sets.
So what you have to do is:
1. Extract the four Aspen textures (or just the two branch ones if you don't mind his bark) you want from Skyrim - Textures.bsa.
2. Extract the Aspen meshes you want to change from the Skyrim - Meshes.bsa
(in both cases use your favorite BSA Browser - I think you said you used BSAAdopt)
3. Create a directory inside the meshes directory (eg Meshes\AngelTrees) and put the extracted meshes in it.
4. Create a directory in the Textures directory, I would suggest - Textures\landscape\treesA (because step 5 will be easier) and put the textures you extracted into it.
5. Now you need to use NifScope to edit all the meshes you have extracted to point to the Textures\landscape\treesA folder as opposed to the standard Textures\landscape\trees (this is the mind numbingly tedious bit). In nifscope you are given a list of 'block details' two of these are called BSShaderTextureSet corresponding to the bark and the branch. They have the usual + for you to click to them open up - inside each one of the options to change is the texture path. double click on the path and change Textures\landscape\trees to Textures\landscape\treesA (basically add an 'A').
6. That by the way is the sum of my knowledge of editing nifs.
7. In the CK it is now easy - duplicate the relevent tree object (eg TreeAspen01) and point it to the mesh in your AngelTrees directory.
When you change a bed that is rentable you need to make sure it is pointed to by the NPC who rents it.
1. Set the beds ownership to that NPC
2. Open up the relevant NPC and you will see they have the RentRoomScript in the script box on the left. Highlight the script and select properties; one of the properites is for the bed, set it to the new bed. .
3. All the other beds need to be set to whatever the faction is that the interior is set to; otherwise the player can use any bed free of charge (that applies to all beds in you mods).