I always use a blow-off until I cold crash because I don't want to put a big cup of water in the fridge. I switch to an S type airlock for cold crashing.
I wouldn't seal the lid unless you're putting it in to cold crash but that's just me. I've gotten too busy to continue to the next step before so I'd be too worried about it not being able to degas. Plus, racking beer that's a little carbonated, more so than just after a regular fermentation, could cause unwanted foaming and aeration.