Lego Dimensions help please

[Titsalinabumsquash]

I've got my boys Lego dimensions as a joint pressie for Christmas, I was going to get them a character pack each to go with it.
What's the difference between the level/team and fun packs please? Do I need a level pack to play with the fun pack characters from that film etc?

We don't have Lego Dimensions yet but this is my understanding (we're also getting it for Christmas):

• the whole point is the mix and match thing so no, you don't need a matching level to use fun pack characters.

• the level packs unlock new levels within the game

So, you could get the Doctor Who level pack and it would unlock a special Doctor Who level, but you could get the Doctor Who fun pack and have the Doctor participate in whatever level you were in.

Hope someone can confirm this before I make a huge mistake as I'm telling relatives to buy various bits assuming they don't have to match!