One of the ladies on our birth club board lives in Florida and she swaddled til now - and her lo is just turned 6mo. if it is hot she sometimes has nothing but a nappy under the swaddle. And you can use fan or aircon - just don't blow directly on baby.
For the reflux, have you propped the cot mattress up on an angle? Are you BF or bottle? Remember night wakings, if they are at different times, mean hunger normally, and at this age lo probably needs a night feed still.
My lo didn't scream through the day at this age (because she napped on me, I hadn't found BW yet then) but every night screamed for hours and hours, and it is very tiring. But it does pass.
Will lo nap in the pram. Maybe for the catnap you could do this in the pram to get yourself out of the house and some stress release by walking. Take breaks from this napping business when you can. But do persevere over all, it will be worth it.