[Aerich]

Well, I believe rogue is the only class that has each of the dialogue skills; every other class "pays" for at least one skill as a cross-class skill. However, that may not be an issue if you have weak physical stats but pump Int and Cha.

I'm not sold on the bard/druid combo for a support character. I've used one, admittedly not in HoF, and it always seemed weak. Bard songs are nice, but how helpful is a measly 3 hp of regeneration in HoF? Damage resistance is nice, but it's a drop in the bucket of melee pain. The luck song might be more valuable than war chant in HoF mode, if it affects spells in the same way as Tymora's Loop. To my mind, it's far better to maximize the potential (e.g. high level spells) of a druid by devoting a character to it, rather than trying to mix the druid class into a support character.

I've always liked a rogue/wizard as a "support" character. At higher levels, it can become a powerhouse, but is sufficiently useful at many "support" skills (thief skills, talking skills, item identification) to earn the designation. If you want to make it more of a support character, take more rogue levels, and learn spells with more of a "support" cachet to them - Bull's Strength, Eagle's Splendor, Identify, Haste, Stoneskin, etc. For race, pick any one that has rogue or wizard as a preferred class. Drow for power, elf for style, halfling for roleplay value. I wouldn't necessarily recommend tiefling, because of the hit to Cha, which is the stat checked for talking skills.

For mix-in classes to any "talking" support character, avoid paladin and monk, for obvious reasons. Barb will really just add hp; I don't see rage as a significant addition to a support character such as a rogue/wizard with weak physical stats. The speed is more useful, but not overwhelming.

If you are committed to using a Druid/Bard as your support character, Barb is a good addition (for one level, anyway). Rage can be activated while shapechanged, in the event the character finds itself forced to fight in melee. Rogue is good for access to skills and evasion, as you noted. Two levels is sufficient to get evasion, and that's all I'd recommend if you have another rogue in your party (so as to maximize the benefit for this character), unless you really want cheap access to dialogue skills. Aside from the reasons for taking these classes, I'd be tempted to take more druid levels for the spells. Their summons, in particular, are very useful for HoF. IMO, more druid levels for this character are more valuable than any Barb or Rogue mix-in levels.