Here is the title of the person you're looking for:
Jack of All Trades
Now most Jack of All Trades will be masters of none, although there are exceptions. Honestly if you've already done the mockups then you've already done the UX Design. And if you "want to tinker in real time" that makes you the designer, because that's what a designer does based on that designer's experience.
If this is the case then next you want to hire someone who is an art director to do look and feel, and then a front end developer/production person
Can you get an art director who sort of knows production? Yes, but that person will be weak at production. Can you get a front end developer who can make things look slick by using off the shelf templates? Sure, but the work may not be original. Can you get someone to do both? Yes but that person is going to be more of a rare bird and very expensive. Or they'll be bad at both art direction and production.
Jack of All Trades
Now most Jack of All Trades will be masters of none, although there are exceptions. Honestly if you've already done the mockups then you've already done the UX Design. And if you "want to tinker in real time" that makes you the designer, because that's what a designer does based on that designer's experience.
If this is the case then next you want to hire someone who is an art director to do look and feel, and then a front end developer/production person
Can you get an art director who sort of knows production? Yes, but that person will be weak at production. Can you get a front end developer who can make things look slick by using off the shelf templates? Sure, but the work may not be original. Can you get someone to do both? Yes but that person is going to be more of a rare bird and very expensive. Or they'll be bad at both art direction and production.