How to be more interesting to prospective PhD advisors
You probably don't need to do much if they have already expressed interest. However, if you want to do more, read a few of their papers so that you are thoroughly familiar with what interests them. That should suggest at least a question or two. I think that questions are more useful to you than statements.

You can ask about funding, but the easiest question to ask is for who you should speak to about funding if not themselves. This lets them know you need it and also lets you contact whoever is responsible.