What you are trying to do is no simple process as TFP allows almost unending combinations of elements and textures.The only way to be sure you cover everything in a modified element (eg Wall) is to right click in the Catalogue list on the right of the screen, select Add New and create a wall of your choice and name. Within that wall, on the Trim tab, right click on each element you want to include and again select Add New and name your new trim, selecting the texture size etc. Do that for any part of the wall that needs to be changed. When you replace the original wall with your newly created one it should also include the newly created trim and other elements. If you have part of the wall with windows sills and/or door sills and others not, then it would have to become another wall type. They must stay in the group where you created them. If you move them later it will not find them.
It is possible in Catalogue Manager to change elements for a selected number of elements all at once. For example you can select a number of walls and change all of them at the same time to a certain trim for example. You still of course have the issue of replacing the elements in the models. Once an element is in the model it is it is no longer connected to the catalogue - changes to the same element in the catalogue will not change it in the model. The catalogue change has to be done before it is inserted (or replaced).
I am not sure how you planned to do your presentation but here is a how I have done it previously and some suggestions:
My previous presentations have been to groups of between 100 and 500 and were done using Powerpoint with images all from the same angle but in different colours. It looks very professional to see the identical view suddenly wipe over from one colour to the other. I have ended with the screen then split into 3 (I never give more than 3 choices) so that all schemes can be compared at once and it is possible at that point to get a show of hands as to which they want. I found it best though to print some of each scheme, name them and distribute a 'voting sheet' so each could nominate their 1, 2, 3 preference. This meant that some were not influenced by others and their second preference was taken into account. Usually there was a very decisive choice for one scheme.
Now to answer your other questions:
The idea of using non-specific names seems really good and I have wondered just how that could be done. Where do the names go? I have tried at one point to make use of the ‘favorite colors’ on the Microsoft Custom color wheel but then I it does not work with textures.
Rule 1 - do not use colours - they do not always work - use images (BMP not JPG) of the colour - this is what the Paint textures are. These render consistantly. If the colour paint you want is not there, then use a photo editing program to make one. From the Microsoft colours choose what you want and use that colour as a tiny image (note the size of the Ben Moore paint colours in the Textures folder). You will find this under the same directory on your computer as the Catalogues folder.
The Textures folder on your computer has nearly 10,000 images in it, only a few of which appear in the lists in the catalogue. Within the Textures folder they are usually grouped because they are named similalry. All the Paints for example starting off with Ben M... and a number for each colour. If you name yours consistantly they will be together.
You need to create the textures (colours) first or, if you are using an existing 'paint', select the one you want in the Textures folder (if you use the photo editing program browser you will see all the textures as thumbnails), and save it with your own name (eg 1FrameG, 1FrameR, 1FrameB etc or 1SidingBrownV (for Vertical), 1SidingBrownH (for Horizontal) etc). The number before the name is just so that it will list first in the Textrues folder rather than being mixed through it alphabetically.
Now is where you get to the tricky bit as you have to change the texture names. Your initial colour has to be named 1Frame (for example and we will say that is the blue one) and that is used everywhere that you need that colour in the model. Once the model is ready with all its generic names you go to the Textures folder on your computer (not the catalogue!) find the 1Frame texture and change its name to 1FrameB (the blue one). Now go to 1FrameR and delete the R so it becomes 1Frame instead and so 1Frame is now red (and should show that in TFP after reopening the model.) To change the colour of 1Frame you would go back to 1Frame and add an R (so you know it is the red one) and now select 1FrameG, delete the G. 1Frame is now green.
It is still going to be tedious but not as much as changing every part of every element.
DO NOT do the whole thing - just try it with one colour to be sure the process works. I have done it before but on a very limited scale. Prove it works on a test model first!