Your procedure for successful customers sounds good, with a single modification. This group receives ESIGN's "how e-delivery works" disclosures and then opts in--in a manner that demonstrates success with the necessary technologies. Subsequent statements can be delivered electronically and the applicable federal consumer protection regs (E, DD, Z, etc.) will consider these documents to be "in writing." It's a minor modification, but ESIGN requires an "affirmative request" for e-delivery. Rewording the text for your link or button will satisfy this technical requirement.
As you currently envision the procedure for customers who fail or bail, you will not be able to proceed with e-deliveries to this group. An opt-in is not complete until each account holder passes the "ESIGN test." Since Regs E, DD, Z, etc. require "written" periodic disclosures, you must continue delivering fail/bail statements in paper form until these customers pass the test.