air in the legs] put your suit on zip up put your fingers in your neck seal and crouch down most of the air will escape you might get a bulge on your chest but just squeeze it out keep arms low too most of the air will come out. you can buy ankle weights which help to keep your feet down.
if you do get inverted using your arms to pull through the water do a forward roll the air will return to the legs. the more air in there the harder it is to right yourself.
i always wear a dry suit even in summer i just increase or decrease the layers below by layers i mean multiple shirts, jumpers, microfiber puffer jackets etc i dont bother with under suits anymore in the boat only when i dived. the layers trap air to give good insulation now you will say back to the inversion problem we are only talking a thin air gap heat dosnt travel through air as well as it does through clothing.
with wind chill it's always good to have a coat/cape or even a space blanket to prevent the wind from drawing heat out of the body even a bin liner will reduce heat loss
just think if you have you can add or take away if you haven't you're going to be cold your family will have a bad experience if cold and it dampens the enthusiasm to go again
https://rnli.org/safety/choose-your-...-motorboating#
PBL2 sound advice you will get duplicate info as we are eager to give advice & help but thats good dont forget this won't happen overnight slowly slowly and know your limits have a great time in the lakes.