Group of?Follow

The guardian will be your tank and the minstrel will cover the healing but it seems to me you'll want some heavy DPS in there somewhere. I would recommend replacing the captain with either a hunter (ranged DPS) or a champion (melee DPS).

The champion has a wide selection of multi target melee moves and can also pull with a bow. The hunter has melee skills but is mostly focused on ranged and single target DPS.

The hunter also has a nice selection of transport abilities like "Find The Path" (a group run speed buff) and "Desperate Flight" (a get out of jail free card) as well as instant group travel to several central locations.

This is not to say you couldn't run with the trio you named and still take down most targets... it would just be faster (and maybe more fun) with a dedicated DPS class toon.

I second replacing the captain with a DPSer. The hunter would add some utilities to you group like "ports" around Middle Earth, but champion's DPS and off-tank ability would be usefull as well, maybe needed without a CCer.

In the end, all that matters is that you have fun. 3 toons will be successful no matter what you choose, so pick the classes you each think will be the most fun. There really isn't a "Holy Trinity" in LOTRO like there is in some other games.