Okay so all I know about the companion system is that it has been substantially tweaked so you can order them arround much easier. The thing I want to know is to what extent can you command them in terms of combat style? Like can you tell someone to be a long range stealth sniper?

In Fallout 3 I loved Charon, the only conflicts i found in his character build was that although his highest strength was sneak, he used a loud close range shot gun but engaged enemies at long range.

So, will I be able to configure my companion to compliment my play style rather than hinder it?

From what I've seen, it seems you could possibly do that. But the wheel isnt that explained yet.

... Couldn't you change the weapon your companion was using?
Or will Charon stick to his shotgun because of the DAM? In that case, give him a gun with higher DAM by comparing on the wikia.

The issue with Charon though, is his Shotgun has a High DAM, and it's alot higher than a Sniper RIfle, which the OP is fond of.

Charons shotgun - 55
Callahans Magnum - 65
Fixed. (Unless you decided to blow up Crawler, in that case... Blackhawk? It has 55 DAM.)