Canon-wise it’s difficult to argue against rebirth. It’s not just found in so many formulas and as the natural understanding of the dependent origination. If you think about the alternative to the 8fold path, i.e. the 10fold path, you have right knowledge as the integral 9th path factor.
And Right Knowledge means the knowledge of my own past rebirths, the knowledge of rebirths of beings in general, and the knowledge of the destruction of the asavas. After that nibbana.
So a substantial part of the suttas dealing with the path just have the knowledge of rebirth right there, at the end of the path. That some arahants don’t have the first two knowledges is to be seen as an EBT fact, but a slight bummer for the texts rank arahants with all three knowledges higher.
The arahants who don’t ‘see’ can’t be called agnostics. I’m pretty sure that if we did a magical survey they would all be very much unshakably convinced in rebirth. It’s not direct knowledge, but no agnosticism either. The agnosticism about rebirth is, in Buddhism, a new and mostly western attitude. Buddhadasa is such an exception that he totally confirms the rule.
What I mean to say is that one has to be an agnostic in spite of the EBT, not justified by them.