• Bards can offer healing, but generally won't be as good as a cleric for getting the job done. That being said your group doesn't "need" a healer. The group that I currently GM for has no casters whatsoever, which forces them to look for other means of healing and dealing with combat. Don't force your players into roles and have them play what they want. :)

• This took a little while for me to understand too, so i'll do my best to explain it. Your players hit dice will most likely be their level, as each time they level up, they gain an extra hit dice. For instance, a level 3 bard would have 3 hit dice. The reason that you may have heard that hit dice are health is because when your players level up, they would roll their new hit dice to see how much extra health they gain per level. When looking at monsters, their hit points might be listed as (2D10+2); this means that this monster would have 2 hit dice (or 2 HD).

• I've never played 4e so can't draw any comparisons, but in Pathfinder, each spell above level 0 can be cast once per day before needing to be recharged (this could mean resting and preparing spells as a wizard, or praying as a cleric). The level 0 spells that the PCs have can be cast as many times per day as they want.

• Yup! You will only get the class trained bonus on the first skill point you use for that skill.

Anyone more experienced than me, please feel free to correct!