So, the easier change would work, as long as you don’t need to really track the info for legal reasons. There’s no way to check whether the info has been entered when it’s just a text addon to Display Name. As a separate field, you can mark it required, which seems to me closer to meeting legal requirements. Something to think about?
It’s not an easy task to remove the add input and use HTML buttons, unless you just hide them with CSS. They mimic the same Elements system that you see on the admin side. Needing to get rid of those, and the above separation of fields for what’s in Display Name, makes me lean toward a value in a new plugin to keep track of data.
This is mostly just things to think about alongside the conversations you’re having with your PI.