I haven't really been able to identify it. Could you point to a video in particular where the Fe use is clear?
I don't really think your schooling can be used as an excuse. I'm an asocial maths major myself, but nonetheless, when I talk on video it is very clear that I'm using Fe throughout - the main exception being when I go inward to work something out, and all expression on my face drops. However, this doesn't last long, because it's due to tertiary function use which can't really be sustained.
You're really making Si out to be more perfected that it actually is, which ties in to my suspicion from earlier that you think that you would like to be an Si user, where in reality you are an Si user and just wish to be a perfected one.
As for memory, it's my understanding that Si and Ni have a very different image of the past. I very rarely remember any details unless they are integral to the meaning of the situation. Essentially, I just have a conceptual outline, and I have to try and reconstruct, either through dreamlike imagery or logic/intuition what actually happened in the situation. I believe Si users tend to remember the details more, and are able to recall quite accurately how they were feeling at a particular instant in the past. And also Si is able to see something, and know based on the physical details whether it matches something they've seen in the past, e.g. for immediately indentifying materials and objects, or knowing when something has changed. I can't do this, but I can tell whether the I've seen a particular idea before, even if in a totally different context, or notice if the meaning of something has changed.
Oh and feel free to end this conversation any time. I'm just trying to find some kind of justification for you having Ni and Fe, because so far I can't really see much of either - or at least, I can't relate to how they manifest in you, because quite frankly I think, from what I've seen of you so far, that our thought processes are totally different.