Dear brother, first let me be clear, I neither have expertise in Bible nor time to study it, I am only a student of Quran. My sole source of info is the book itself, though sometimes it so happens that other sources corroborate what is in the book. This is of no concern to me either. No, I don’t have to believe in Biblical stories if they clash with the book.
Second, the book is in Arabic, which is not my language. So I read various lexicons, use tasreef-ul-ayaat and context methodology, etc., to arrive at suitable meanings as per my understanding. If my so-arrived understanding agrees with what is understood and written by previous/present scholars, it gives more credence to my understanding, but if it clashes with either of them, I examine their arguments and then compare them with my arguments, discarding whichever departs away from the bookas per my understanding. I grant the same right and privilege to all.
Now to your questions and observations. In this respect I ask you to please refer to a lexicon, such as Lughat by Parwez or Lane. Let us just review 2:133, 170:
[2:133]: “ … Jacob, when he said to his sons, "What will you worship after me?" They said, "We will worship your God and the God of your FATHERS/FOREFATHERS (ābāika), ABRAHAM AND ISHMAEL AND ISAAC - one God. And we are Muslims [in submission] to Him."
[2:170]: And when it is said to them, "Follow what Allah has revealed," they say, "Rather, we will follow that which we found our FATHERS/FOREFATHERS/UNCLES (ābāanā ) doing." Even though their fathers understood nothing, nor were they guided?
Please note, all three, ABRAHAM, ISHMAEL, and ISAAC are referred as “Fathers” of Jacob in 2:133, in fact, ISAAC is Father, Ismael is UNCLE, and Abraham is grandfather to Jacob.Thus, it is abundantly clear that this term would always have all such meanings present and could only be separated if context permits doing so. Same is true in 2:170, for example.
Now let us examine [6:84]: “And We gave to Abraham, Isaac and Jacob - all [of them] We guided. And Noah, We guided before; and among his (Noah’s) descendants, David and Solomon and Job and Joseph and Moses and Aaron. Thus do We reward the doers of good.”
David is more than a dozen generations removed from Ibrahim, Solomon is a son of David, Ayub (Job) and Joseph both grand-grand uncles of David and Solomon, Musa and Aaron brothers and Grand-grand uncles/cousins of David and Solomon. In fact, there is only one biological father-son relationship in 6:84. Similarly, there is no father-son direct relationship in 6:85 except Zachariya and Yahya. Same in 6:86, there is no direct son-father relationship. Now to 6:87:
[6:87]: And [some] among their (ALL prophets mentioned in above verses) fathers/forefathers/uncles and their descendants and their brothers - and We chose them and We guided them to a straight path.
Thus, 6:87 is a blanket statement covering all possible relations in previous verses, clearly establishing YOU CANNOT USE 6:87 TO BLANKET CONCLUDE WHAT YOU DID. It is the language brother, one must respect and adhere to.
49:13 will be addressed when I start analyzing the birth of Jesus. You will have to wait a bit.