As far as temp for the gruel - I'd feed it room temp or maybe a tad warmer. I don't think that heating it is necessary - and there is always the risk of OVER heating or having hot spots that can cause burns.
Use warmish water, or room temp water. I'd think cold water might chill him some so I'd stay away from cold water.
Use warmish water, or room temp water. I'd think cold water might chill him some so I'd stay away from cold water.