Headed to Maui in Nay, wife is taking lessons, she has booties and a helmet, but her wetsuit is a 4/3. She wants protection for legs and feet. Any recommendations welcome.
coup

I suppose this is personal tolerance related but I've never worn anything but board shorts in Maui. My wife is really uncomfortable with the cold and spends the whole trip snorkeling without a wetsuit as well.

if your wife is wanting sun protection then she can get long sleeve rash guards, spf 40 leggings, and some tropical rated boots.

Just got back from there. Never felt the need to wear anything warmer than a rash guard.
Sun protection definitely recommended.

All personal preference. Water is not as warm as and a lot of people wear shorties. My wife who is a beginner wears 2mm, long neoprene pants. Protects the knees and the shins.

Rip Curl G-Bomb 1.5mm Long Jane, or Roxy Rise 1.5

Lycra pants with an impact vest would be warm enough also. Any brand reef bootie with some protection from foil and rocks is a good idea.

May is the last cold month with a lot of wind, but it's still mid to upper 70's water and air temp 80-85, so as long as you are moving you're fine in a swim suit. Standing in waist high water with wind for a lesson might be a touch cool with just a swim suit.