I'm pretty sure you can title the accounts accordingly... what matters for the Regulations is that you maintain proper reserve accounts and tracking of those balances.
It may be an issue of confusion though which would leave you "open to regulatory criticism." Not because it's not technically right, but as you yourself said it might as well be called a NOW or transaction account.
Some additional thoughts to ponder... Fraud, a "savings account" would be noticed after 6 transactions, so telling a customer that they are in a savings account that happens to have fraud with more than 6 transactions in a month might come back to bite you... Which leads me to start thinking UDAAP... in terms of how hard that later bite might be...
In life, there is a lot less that could get better and a lot more that could get worse.
MBA Fin/MBS HR
My views only!