Living, Studying and Working

Hello everyone. ILve been doing a huge research about living and working in Japan, which have left me with another huge bunch of questions, which I will divide in paragraphs:

----- Studies and personal case-----------
ILm currently young, doing my FP (alternative to baccalaureate here in my country) and I would really like to finish my studies and continue them in Japan, and then working there. When I finish my medium and superior grade of FP in the future (2 years both), I will be 22 years old, with the possibility of joing University. Is it really necessary to study in a japanese university for having more possibilities of getting a job? ILm saving money in a bank account with a part time job I have in a factory, so I donLt know if itLs better to go and take 2 years of language school and then try to join University, or 2 years of language school and then doing 2 years at a Senmon Gakko. What do you guys think?

-----Language------
With that long text you will probably ask "2 years is not enough for learning such a difficult language". I also asked that my self, so I started studying, giving me 5 years to study on my own. Do you guys think that is enough for joining a language school and continue my studies without any problems? (ILm talking about N3). My studying routine is very strict, 5 to 8 hours a day (every single day), using official books (no "watching too many anime"), watching videos about the grammar, reading manga with furigana... and then I would try other options like communicating with japanese people in chats, watching doramas, etc. I really like languages, but I love japanese, and I am very determined to study the language and take it to the highest possible level, both to live there and for the working world. What do you guys think? 5 years for having the N3 and then 2 more in Japan for polishing it before starting a Senmon Gakko?

---Living---
I researched about transport, costs of life, I did A LOT of maths... but I still have doubts. Like I said, I have a part time job which pays me 600€ (650$) every month, which I save in my account. I calculated that in 5 years I will have the huge amount of 30.000€ or more (almost 33,000$, 3.5 million yen) plus the money I earn until I travel to Japan after paying the school and purchasing the ticket, because ILve seen you need to start doing the paperwork 6 months before the school starts (30.000 aprox - 1 year of KAI - ticket - GuestHouse= x + 5/6 months working before travelling to Japan = 30.000 again) , which I will use for the 2 years of school (Kai, year by year, which is cheaper), for living in Japan (with tricks for saving money, eating cheap, not drinking or smoking, etc) and for all the basic things I want. I will apply for a baito there (ILve been a lot in Shinjuku ward which pay 1200 yen per hour), so I can pay everything and still save some money for the Senmon Gakko. I calculated everything, from when I arrive at Japan at Haneda, where I will get the SIM card which I will use for getting the Zairyu the next day (also the aiport train ticket, GuestHouse, food) until the day I rent an apartment (also Suica/Pasmo, food, rent + extra one-time expenses, phone plan, water, gas...), and if my estimations are right... I will have a big account left for paying 2 years of a 1.200.000 yen Senmon Gakko. Are there any other expenses? Like other taxes farther than the health insurance, or other extra things.

----Working----
When I finish my Senmon Gakko, I would start looking for a job. I havenLt researched about this topic yet, I have only seen a few videos and pages that talked about a 80%-85% people that studied in a Senmon Gakko had for getting a job. ILm a little bit scared about the fact of having a N2-N1 for working, because as I said in the Language section, I donLt know if 2 years in KAI starting with a N3 (almost N2 if it is possible, giving the language a lot of dedication) will be enough for joining a Senmon Gakko and understand technical japanese without problems. Should I search for one dedicated to foreigners or a better rated one?

----EXTRA questions----
- Is the MyPersonal number REALLY necessary for anything? Like opening a bank account for renting an apartment, and, how do you get it?
- Is the Zairyu Card hard to renovate when I leave the GuestHouse and start living in an apartment?
- Is N1 really necessary for working as programmer, for example, or having a N2 is a better option?
- Is Nattō that bad? (funny question everyone wants to know xD)

If you have come this far, I want to thank you for reading, and also apologize for my bad english. Although all this only sounds like a dream, with effort and dedication everything is possible! I wait your responses!

For Food: I think,it is better if you eat buffet restaurant cost 1000 yen per visit,so 30 times cost 30000 yen.It will save you time to shopping from Local super market,save time to cook,to prepare,to go or buy food items.In that time,you can hangout with your friends or do some part time job.(28 hours per week).

You did a Lot of calculation. But when I go first time in Japan,in that time
We pay 3% vat.now 10%.Somehow I got scholarship from Ritsumeikan university, Located in Kyoto.They also have other campus, such as Biwako kusatsu campus.well,I get 100% scholarship. So I paid nothing.
Our teaching medium is English based.But you Learn Japanese Language course as a compulsory.Hope this will help.

- Is the MyPersonal number REALLY necessary for anything? Like opening a bank account for renting an apartment, and, how do you get it?
Yes - some banks require it for opening a bank account as an example, and some employers may require it for tax reasons. I also needed it for my home country banking/tax reasons. You apply for one (online).
- Is the Zairyu Card hard to renovate when I leave the GuestHouse and start living in an apartment?
You do move-out/move-in notifications with your local city hall - pretty easy.
- Is N1 really necessary for working as programmer, for example, or having a N2 is a better option?
The people I know that learned Japanese to fluency only bothered with N2.
- Is Nattō that bad? (funny question everyone wants to know xD)
No, I don't even think it smells bad, but I don't bother seeking it out as a food. Depends on the person.

Thank you very much guys, now my doubts are clear.