I will answer this part of the question because the rest of your questions only raises more questions lol As most of us here including myself have had learn by experience and you will too in time so be patient and take your time. And KrX is very knowledgeable and he has been my Yoda of WinReducer
Actually is quite good at pointing you to a link and telling you to go and read some more! haha How can I change my choice about removing different components ?
If you want this to be fool proof this is the rule I have always followed and I know that WinterStorm wrote this as well somewhere else on this website. But the best answer is ALWAYS start with a good ISO and you can take your pick from the ones people here have used. If ever in doubt about whether an ISO is good or not, I take the safest route and download it again from the original source (usually Microsoft). Be sure to trash all the others.
And then start out with one of these two choices:
Choice 1) Start all over with none of the presets changed and then go from there. I learned a long time ago too, don't change so many presets that you lose track of which ones are doing what. Always be certain that you choose your presets carefully. This is vitally important to be an effective tester. If you use an image that was created by WinReducer and try to apply some more presets then you are only inviting trouble and you have only yourself to blame. More importantly though is that method is NOT a valid test of WinReducer and defeats the purpose of helping us test.
Choice 2) Again use only a fresh ISO as I suggest in Choice 1 but this time use a previous set of presets that you already used and they will be listed under YourWREX100 directory/Home/Presets/LastUsed. You might wanna clean this directory out especially if you can't remember which ones were good and which are bad. And when you execute WREX100 and after you get your ISO of choice mounted then click on the LOAD button and select your WCCF file that contains your presets that you want to work with. Also take note of the Clear Settings button and that's a nice little panic button if you forget what your doing
Now you will notice that only the presets you used before are now again set, however, now we finally get to your original question above and now if you want to change your mind and put that component back in, now is the time to do so. Likewise, if you wish to select more components this is where you can do that as well.
Hopefully I at least answered that one question in particular and it may answer the others as well.