The withdrawal agreement has not been ratified, and it is very unlikely that it will be in its current form. This is not least because the current government of the UK are opposed to many aspects of the treaty, including the backstop arrangements for Northern Ireland. The renewed focus on the Irish border is a result of the UK government trying to renegotiate the treaty with the EU to address their concerns.
All this said, if the treaty were to be ratified in its current state (or something very close to its current state) these new options would be irrelevant. The primary purpose of these plans is to replace the backstop in a renegotiated withdrawal agreement, with a view to making it more palatable to some MPs in the UK. If the EU were to agree to these plans, they would come into place if a single customs territory were not to be created.
In my view, the reason these plans are being given so much coverage (as the original backstop was) is because most people (at least in the UK) don't expect the negotiations in the transition period to be fruitful so these fallback plans are more important than is perhaps initially apparent.