And what you are dealing with on here from most as to some of their most repeated assertions, is not actually Mid-Acts based.
It is a hybrid of two opposing schools of thought - Acts 9, or Mid-Acts, aka M.A.D. fused with various Acts 28er views.
Just as, say, Interplanner's views differ somewhat, from that of others who hold most but not all his views (though he and such as he all hold that much that the Dispensationalist asserts is literal, is actually allegorical).
Though eternally saved and sealed upon their belief that Jesus was their Prophesied Christ (John 1-5, etc.), the Twelve and their converts, along with James; remained under the Law, just as reminded to by the Lord in Matthew 5; in Matthew 23; and elsewhere.
Because The Law is THEIR IDENTITY "in the sight of the nations" they and the Twelve Tribes of Israel will one day be God's Royal Priesthood over...
Exodus 19:5 Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine: 19:6 And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel.
Deuteronomy 4:5 Behold, I have taught you statutes and judgments, even as the LORD my God commanded me, that ye should do so in the land whither ye go to possess it. 4:6 Keep therefore and do them; for this is your wisdom and your understanding in the sight of the nations, which shall hear all these statutes, and say, Surely this great nation is a wise and understanding people. 4:7 For what nation is there so great, who hath God so nigh unto them, as the LORD our God is in all things that we call upon him for? 4:8 And what nation is there so great, that hath statutes and judgments so righteous as all this law, which I set before you this day?
Isaiah 61:6 But ye shall be named the Priests of the LORD: men shall call you the Ministers of our God: ye shall eat the riches of the Gentiles, and in their glory shall ye boast yourselves.
Ezekiel 11:19 And I will give them one heart, and I will put a new spirit within you; and I will take the stony heart out of their flesh, and will give them an heart of flesh: 11:20 That they may walk in my statutes, and keep mine ordinances, and do them: and they shall be my people, and I will be their God.
Matthew 5:17 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. 5:18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. 5:19 Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
Matthew 19:28 And Jesus said unto them, Verily I say unto you, That ye which have followed me, in the regeneration when the Son of man shall sit in the throne of his glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel. 19:29 And every one that hath forsaken houses, or brethren, or sisters, or father, or mother, or wife, or children, or lands, for my name's sake, shall receive an hundredfold, and shall inherit everlasting life. 19:30 But many that are first shall be last; and the last shall be first.
Matthew 23:1 Then spake Jesus to the multitude, and to his disciples, 23:2 Saying, The scribes and the Pharisees sit in Moses' seat: 23:3 All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not.
This was why circumcision and keeping the Law is not an issue in Acts until Acts 10.
Ten...chapters...later.
Because THEY REMAINED under THEIR God-given Law as His PEOPLE.
Only AFTER Unbelieving was concluded "under sin" with the Gentiles by The Law, per the end of Acts 7; the end of Romans 2 and into Romans 3, did that requirement no longer apply to Gentiles.
Nor to those lost Jews saved AFTER Unbelieving Israel was concluded "under sin" with the Gentiles, by the Law.
Acts 21:17 And when we were come to Jerusalem, the brethren received us gladly. 21:18 And the day following Paul went in with us unto James; and all the elders were present. 21:19 And when he had saluted them, he declared particularly what things God had wrought among the Gentiles by his ministry. 21:20 And when they heard it, they glorified the Lord, and said unto him, Thou seest, brother, how many thousands of Jews there are which believe; and they are all zealous of the law: 21:21 And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to forsake Moses, saying that they ought not to circumcise their children, neither to walk after the customs. 21:22 What is it therefore? the multitude must needs come together: for they will hear that thou art come. 21:23 Do therefore this that we say to thee: We have four men which have a vow on them; 21:24 Them take, and purify thyself with them, and be at charges with them, that they may shave their heads: and all may know that those things, whereof they were informed concerning thee, are nothing; but that thou thyself also walkest orderly, and keepest the law. 21:25 As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication. 21:26 Then Paul took the men, and the next day purifying himself with them entered into the temple, to signify the accomplishment of the days of purification, until that an offering should be offered for every one of them.
Verse 21 one there was true of Paul..
Romans 7:1 Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth?
7:4 Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God. 7:5 For when we were in the flesh, the motions of sins, which were by the law, did work in our members to bring forth fruit unto death. 7:6 But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.
It is also obvious on Acts 21 that even THEIR entering into the Temple at Jerusalem to worship, as in, say, Acts 3, was in accordance with a water cleansing ritual.
Their intented Priesthood over the Earth; their water cleansing each time they went into the Temple - all of it ripped off by the RCC.
While, to hybrid their aspect of the gospel of Christ (Law Keeping as their National Identity) an aspect the Gentiles were not under within their aspect of the gospel of Christ - to fuse those two together - was to arrive at another gospel; one that was neither of those two aspects, and thus, not another; at all.