Bathing and showering are different. We take showers but don’t give the kids baths. Also they don’t have a need for it - I have the need for them to be clean. That’s not the same thing at all.
How do they not need it? My kids get irritation in the diaper area if not washed up at least there.
I pour soap into a cup of water and then pour it over the body/hair. We do not squeeze out hair but pat with a towel very lightly.
If your concerned, skip the hair but let them sit in the bath with bubbles.
We wash our hands and wash dishes in hot water on yom tov. The issue is not the hot water it’s shmearing soap and shampoo and squeezing the hair to get the shampoo out. We asked and was told it’s not so simple and better not to