EQ2: Group Input

I've never boxed EQ2, and only played it a bit - But I boxed extensively in WoW and EQ1.

Now, my wife plays a LOT solo in EQ2 - But finding some stuff hard, so I was debating bringing up a team to help her do harder 1 groupable stuff.

So, I need input on what class combos to level - Goal is to do 1 groupable stuff, boxing a full group (or -1 slot for wife, who plays beastmaster).

Some thoughts:

1) Do I need a tank, I think that's likley - If so, which one is best? I was gonna go SK or Pally based on my EQ1 preferences

2) Can any of the healers do well enough to also be slower, or could perhaps 1 dps be chanter and do slow?

3) And then just fill out with range dps, wizards? or any other better choice - Or do I need to worry about CC etc?

Any input appreciated!

or is perhaps 5 necros and a healer the way to go?

I'm only lvl 30, but I've had success with a group of 3, with 3 mercs for heroic/group content.
I use a Berzerker, Dirge and Inquisitor. I have mercs to help tank, dps and heal.

How reliable are the mercs? And are they better on "main" roles rather than dps?