Well, I usually get ESFJ as test results and Fe and Si as most developed functions in tests and do identify with that. BUT I also have rather high Te (according to functions tests and I also relate a lot with the descriptions) and I can be somewhat "ESTJ"-ish (I only found out some years ago that life is easier when I'm nice to people instead of telling them that they should be shot for ignorance/stupidity ;-) ). Also, functions tests usually attribute me higher Ni than Ne, although Ne should be/is my 3rd function...
And I once took a test for "me as a teenager" and got ENTJ.
So I made up a little "theory": As far as I know very few people are 100% extroverted or introverted, and I can imagine that N/S and T/F work in a familiar way. So if someone really has 50:50 N:S (or F:T for that matter) they could have elements and functions of both types... Like, in my case, I have strong Te and Fe and can be STJish as I said. My preference for J (over P) makes/would make me an extroverted thinker (and introverted intuitive), although I should have Ne as 3rd Ti as inferior function (Did I use Ti making up this stuff? I don't identify with Ti at all honestly...). So I'm a bit of an "F/T-ambivert" (but a lot more sensing than intuitive!), similiar to the ambiverts which are "in between introverted and extroverted".
But on the other hand, I'm pretty sure that my Te comes from nurture/was and is developed by trying to explain to my ISTJ dad (who doesn't understand my Fe at all) how I feel.
I also read somewhere that your first two functions define your type, and that the others aren't always developed/used in the same order the theory suggests.
And somewhere else I read that Te and Fe (and Ti and Fi) aren't opposites, but rather two ways of doing basically the same thing, while Fe and Fi aren't similiar at all. I could relate to that a lot - I do see Ti as being the most different from Fe when it comes to those functions. But I have no idea whether you can apply this to Ni/Si vs. Ne/Se - maybe not because N and S seem so different... (says an SJ who doesn't really understand Ne or Ni to be honest^^)
I agree that you should look more into which functions you use and how.
Also remember that a type is not a stereotype - I'm definitely not a "stereotypical" ESFJ, but nevertheless, I do agree that this is my type/that Fe and Si are my strongest functions that define how I think and react to the world, etc.
No one is a stereotype, and it's not like Feelers are less intelligent or more irrational than Thinkers or whatever.
For me, MBTI is about understanding yourself and others (better). So I would just pick what makes sense for/helps you. If you feel like a hybrid and that concept helps you understand yourself, go for it! It's just a theory and you're not hurting anyone by not agreeing 100% with what it says ;-)