HI JOLLY, our cats here have dried food and water all the time so i wouldn't worry about over feeding him, As for a collar , well its entirely up to you if you want him to wear one but my opinion is if he is going to be an "outside" cat then theres always the danger that he could get the collar caught up somewhere when he's off investigating his neighbourhood, so my advice would be if you do want to put a collar on him get the type that has a short piece of elastic on them so then if it does get caught up at least it will stretch and he should be able to get out of it. as for sleeping in his bed , well we have 3 here and they have beds everywhere , on radiators on climbers etc etc but they sleep everywher except for in their beds, sometimes ours too sleep on the laminate flooring , im sure at this time of year its nice and cool for them. everything your doing for him is right so i really wouldn't worry, i hope some of this helps, good luck with the kitten.
best wishes...................Chris.