They do for wales because you don't have a second team like the Saxons . As for as I'm aware he's committed to Wales
It's a bit more complicated than that. It only counts when Wales U20 play against another union who's nominated their U20 side as their second in line. France is the obvious one.
I'd still expect Williams to want to play for Wales though, so it probably doesn't matter. He's got a great chance in being involved in the 6nations imo.
As for the topic at hand, I think only Roberts and Faletau will count as wildcards, as both had firm offers on the table from a region/NDC, but chose an English club regardless.
Noth had no firm offers from within Wales. The Blues offer for Charteris apparently came after he signed.
Where it could get very interesting is next year if AWJ, Halfpenny and anyone else (e.g. Webb) opt for English/French clubs, as he'll still only have 3 wildcard choices.
Where I see Gatland's law really working well to draw players back is fringe players who are still pushing for international honours. The likes of Matthew Morgan, Bradley Davies etc. when their contracts expire. It'll put pressure on them to return to Wales, because they know they won't be selected as a wildcard ahead of others.
Anyone know if the rule will apply to players who haven't previously played in Wales. If a region offered a contract to say Francis or Moriarty when their current contracts expire, would they have to take Gatlands law into account, or is there another loophole?