It looks like you have the basics covered to me.

I'd recommended getting the addons Jamba and Smartbuff. Maybe Healbot if your main is the priest. I used Healbot (2nd monitor, my priest is a slave toon) until I started doing more difficult instances.

Also, doesn't harm imply exists??? I forget.

You might want to bind a single key to a different movement direction on your four slaves as well, this spreads them out.

Priests first heal is Lesser Heal, I believe. Maybe Renew too?

If your main is the priest, I am not sure you really need a macro for healing? Although, with focus you might. I don't typically use focus for this type of thing (at least not yet), so I don't know.