Yes cause I believe the Apostles viewed non Jewish believers as more than sons of Noah but 'sons of Abraham. I'm in an discussion somewhere else about this. In Judaism(then and now) a son of Abraham is a convert, in the Apostolic sense if you will it's not a convert(becoming a son of Israel), so we have to be careful with this not to portray the wrong idea.
The problem is your definition of a convert is anachronistic, when we speak of Abraham and gentiles being heirs to Abraham, even if only in a "spiritual" sense, Judaism would never accept this, so we have to understand this from scripture and not 1st century Judaism. Paul describes this as something that existed in the scriptures, but was not revealed until the time of Yeshua. Thus to compare it to 1st century Judaism is anachronistic and faulty.
The root of the tree is the patriarchs. The root being the patriarchs doesn't belong to Israel only.
The point is this, the tree does not belong to Gentiles, however it naturally belongs to Jews, gentiles get grafted in. The point is, the Jews do not leave their tree, gentiles in the metaphor do leave their tree, to be joined to a tree that is not theirs. This is usually seen as a form of adoption, if the tree represents a family, then the gentiles are not by nature part of that family, duh, however now in the Messiah, they have been adopted or brought in. This is different then how Judaism views it, and Judaism would never accept such a possibility, thus we must look to the scriptures instead.
Paul also in Ephesians says that gentiles are now part of the commonwealth of Israel... These cannot be simply set to the side as having purely a spiritual meaning with no literal implications, yet most arguments presented from even stances that you hold, fail to acknowledge what this means in a literal sense. You at least stated you do see some literal aspect to it, but you never go into details as to what that means.
Concerning Judaism, my point is not to bash Judaism, no need and worthless, I have no point in bashing Christianity either, both have been used by God to carry out a major purpose. However just as we know Christianity's worldview is flawed, especially concerning Jews and Judaism, we also know Judaism's worldview is flawed concerning the Messiah and His followers. The error some are making today is in trying to adhere to Judaism's world view in MJ circles. This can only happen by erasing the additions the Apostolic Writings have brought, some say it is compatible, but if we ask the simple questions concerning Judaism with comparison to the Apostolic Writings, then we can see, that they are in fact not compatible, at least in whole. I brought this up, because I noticed that part of your definitions are by trying to hold on to Judaism's worldview and definitions, then trying to make them compatible with the Apostolic Writings. You said you would not want to be Paul, because of the radical things he stated, exactly, because they did not line up with Judaism in his day and neither today, creating conflict.