It's impossible to be an X first off, and your "Ni" is probably Si working with Ne. With Si you get a database of information that you gather, and with Ne you can expand on that and see the possibilities of that database, or what could possibly come out of it. Si is the jungle, Ne is the trailblazer. You're just a healthy ISTJ in my opinion, and also a very obvious ISTJ in my opinion.
The Pi functions can look alike... That's for sure. All of the functions can look alike in some way, Ti for Fi, Ni for Si, Te for Fe etc.
As for your assessment, it seems we are similar in this. I'm tied at the top for my main two functions (Fi and Ne), with Te coming next, making myself seemingly built like an ENFP. But I know that I'm not an ENFP, no way. I'm an obvious introvert. That test is good for showing your strength that you have with your functions in my opinion, not necissarily a good thing to type yourself with. It's good that you have a strong Ne. You seem to have the strengths of an ESTJ, but you are built like an ISTJ, according to your functions. I mean built like an ISTJ with how you use your functions, the same way I have the strengths of an ENFP, but I'm built like an INFP.
I think I'm not being too clear here... But my Te is abnormally strong for an INFP, it has the strength an ENFP's would. But I use it in the manner an INFP would that's healthy. You can apply that to yourself with the ESTJ Ne.