Are there any early Judaic sources that discuss whether all firstborn sons HAVE to be redeemed, or can any firstborn son be dedicated as a priest - and NOT redeemed?
Note: Like, the Tannaim, the Mishnah, or Talmud.
At the very least, Scripture is clear that firstborn sons NOT dedicated as priests must be redeemed.
Context:
Initially, priests seem to have been taken from the "Firstborn Sons", not just Levites :
Exodus 13:2, (Shemot) - "Sanctify to Me every firstborn, every one that opens the womb among the children of Israel among man and among animals; it is Mine."
Number 3:41, (Bamidbar) - And you shall take the Levites for Me I am the Lord instead of all firstborns among the children of Israel. And [take] the Levites' animals instead of all the firstborn animals of the children of Israel.