FYI: This is my 1st pkaythrough so no spoilers, please

I currently have the following companions:
- Shadowheart,
- Laez'el,
- Astarion,
- Minthara (just about to romance her).
Out of the above four companions, which would provide the best experience for my 1st playthrough.
Also, what classes would pair well with my tav (I am a dual-crossbow-wielding Swords Bard) so I can respec them accordingly. My current idea is a frontliner (most likely open-hand monk), a spellcaster, a life cleric for healing and me.