Nice to meet you Jazzy...
House of Judah
One point of contention , keeping Torah doesn't make you Jewish , being born of the tribe of Judah, or being of the nation of Judea (tribes of: Judah, Benyamin or Levy) would make you "Jewish" , or converting to the doctrines of the Pharisees , or the modern Rabbinical Judaism might make you Jewish by religion. But following Torah " the commandments of God" , just makes you a faithful servant of the Most High, and great in the kingdom according to Matthew 5:19.
Keeping the commandments for gentiles?
1Cr 7:19 Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God.
What's strange about this verse in 1st Corinthians 7:19 ? Isn't being circumcised a commandment of God? It is...
Let me suggest an answer , the term "circumcision" is not referring to an act of keeping the commandments of God, but a reference to a religion, or a peoples i.e. Greek "ethos" and not meaning those literally circumcised, rather those "of the culture of circumcision" that are distinctly Jewish in this context, those "of the nations" i.e. Gentiles are not identified in this way.
According to Paul it doesn't matter if you are ethnically and culturally Jewish " of the Circumcision " or " of the nations" ; the weighty matter is keeping the commandments of God. Literal Circumcision is a commandment of God , so Paul is not using the term "circumcision" the way you think he is, He is meaning it as a cultural and religious identifier.
Becoming Jewish would be to assume a cultural heritage that is uniquely Jewish , that would be silly to try to do unless you were in fact Jewish by birth or adoption or something like that.
Yet he is very clear , the weightier matter is keeping the commandments of God.
House of Joseph
There are at least 10+ other tribes , that comprise Northern Israel that are the exiles of Israel ... Generally known as the tribes of Ruben, Simeon, Dan , Naphtali , Issachar, Asher, Gad , Zebulen, Joseph ( Ephraim and Manasseh ) None of these tribes would be considered to be Jewish , they are referred to as the House of Joseph , Israel , or Ephraim. They are Israelite , just not Jewish.
Regarding Act 15
The question was what the " non- Jews" had to do to be saved. The Believing Pharisees insisted they had to keep the customs of Moses and be circumcised to be saved.
Young's literal
Act 15:1 And certain having come down from Judea, were teaching the brethren -- `If ye be not circumcised after the custom of Moses, ye are not able to be saved;'
The Greek word used for custom is Ethos not nomos ( law )...
This is an important distinction from following the instructions of the Torah. The Pharisees had added volumes of commandments and heavy burdens beyond the Torah and exalted themselves and their own teachings above the written word of God. They still do today, it is called the Oral Torah, a separate set of man made laws and traditions codified in various writings; the Jerusalem Talmud or the Babylonian Talmud. Regardless they are additions to the Torah.
Deu 12:32
What thing so ever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.
D
eu 4:2 Ye shall not add unto the word which I command you, neither shall ye diminish [ought] from it,
that ye may keep the commandments of the LORD your God which I command you.
These additions of commandments were expressly forbidden in the Torah, so the "Jews" , both Pharisees and Rabbis have broken this commandment by their traditions and additions to the law. And Yeshuah was very clear in his Words and Actions; he didn't follow or endorse their traditions or additions, and called them on it several times in the Gospels.
Mat 23:4 for they bind together burdens heavy and grievous to be borne, and lay upon the shoulders of men, but with their finger they will not move them.
Mat 15:3 But he answered and said unto them, Why do ye also transgress the commandment of God by your tradition?
Back to Acts 15 , the question is “ what” must the gentiles do to be saved? The Pharisees proposed they must be circumcised after the customs of Moses. You have to take into account who is asking the question. It was “Certain” of the sect of the Pharisees (The Separated ones.)
Act 15:5 and there rose up certain of those of the sect of the Pharisees who believed, saying -- `It behoveth to circumcise them, to command them also to keep the law of Moses.'
You have to understand these are the same group of People that Paul took to task in Galatians, and Paul was once a Pharisee himself. They don’t keep Torah themselves, but make thousands of rules in addition to the Torah, and many of those traditions violate the Torah. Just because they believed Yeshua was the Messiah didn’t change their doctrines and sense of authority. They wanted to Yoke, the new converts into Pharisaical Judaism, which included the Oral Torah (doctrines of men), and the written Torah, the law of Moses.
Do you have to do that to be saved? No, you have to receive the free gift of Yehovah, and trust in the name of his Messiah, Yeshua. You don’t have to keep the rules and regulations of men, or keep Torah to be saved; salvation is a gift of God. However, is that the end or our journey? No it is not, and it wasn’t the end of the journey for those Gentiles believers either.
act 15:10 now, therefore, why do ye tempt God, to put a yoke upon the neck of the disciples, which neither our fathers nor we were able to bear?
The burdens and the "Yoke" ( teachings ) of Pharisaical Judaism were not the Torah of Yehovah , it was the doctrines and the teachings of the Pharisees.
James has more instructions
Act 15:19 wherefore I judge: not to trouble those who from the nations do turn back to God,
Act 15:20 but to write to them to abstain from the pollutions of the idols, and the whoredom, and the strangled thing; and the blood;
Act 15:21 for Moses from former generations in every city hath those preaching him -- in the synagogues every sabbath being read.'
These new converts are turning back to God, they have begun a
process in which the Holy Spirit is leading them , through their new High Priest Yeshua, not a group of Pharisees , who in all honesty have a lot of unlearning to do themselves. James tells the gentiles to abstain from things that would make them unclean , so that they can go hear the Torah on the Sabbath , in the synagogues . By the way this is how a proselyte would be treated. That is James is treating them as babes and converts , and opening the door for them to learn and grow in knowledge and grace , while hearing Moses being read.