How will they go? Poorly probably. I think part of Japan getting a SR team was placing a limit on ex-pats allowed to play. I'd imagine it will more closely resemble the national team of Japan. The Argentina team is looking good so far, I expect it to be very competitive in the SA conference. How will the Kings do? Well it's a bit of a joke SA are getting yet another Super Rugby team + they get an easier double conference. They have really f*cked up Super Rugby.
A Pacific Island team was and always has been a completely terrible idea. Truly awful.
1. All three PI unions have faced multiple corruption cases. Samoa recently has been one of the worst run unions of any sport. They refuse to even pay their international players fairly, how will they run a pro team?
2. Where will their infrastructure come from? The stadiums are all too small, ticket prices would by necessity be too expensive for it to be profitable. Who pays the players? There was talk of them using Eden Park. Great, so the Blues which are already struggling can see a continued loss of support and revenue, likely subsidized or fully funded by the NZRU.
3. Where does the revenue get generated from? What are the market benefits both in terms of SANZAR, and growing the game? Will Samoa, Tonga and Fiji suddenly provide a market an increased television audience? It's a market of only slightly over 1 million people who are already passionate about rugby. There is no benefit. Technically, Port Elizabeth has a much larger market, infrastructure and population (just sadly SA doesn't have the depth to justify a sixth team, particularly with players leaving to Europe).