Help with Toddler before baby arrives!!

We have our second baby due in Mid August. Our toddler is almost 2 (April) and we are looking to transfer him to a toddler bed before baby arrives. How do I make sure that his room is absolutely toddler proof? How did you make it an easy transfer? What size bed (toddler, twin, full size, no frame, on the floor?) He is an extremely light sleeper and He has a speech/language delay so I’m questioning if he’s truly ready for this yet. But I don’t want to wait and have him crawling out of the crib when baby 2 arrives then it be chaos! (He’s already trying to climb) posting pictures in the comments of my lay out concerns! Thanks in advance mamas!