Both W101 and Bayo2 are funded by Nintendo, so I guess even if they bomb Platinum won't be hurt (aside maybe image wise).
Generally speaking, the health of an independent developer has no direct connection to how their games sell, because they A.) don't fund their own games and B.) they get almost no royalties from the sales of their games even when they sell millions upon millions of copies.
What *is* important though is that they always have work, because if they don't have a project for even 2-4 weeks, they won't have money to give out when it comes time to pay salary.
Now, obviously indirectly the sales of their games are important, because it determines the likelihood that they get work and the chances that they can become one of the rare independent developers who do earn notable royalties for their work, but this is why we see some developers launch a game that sells very well and then close up (Team Bondi), while others launch a bunch of bombs yet stay open (Ninja Theory), because all that matters is that a publisher is willing to sign them and have them make a new project immediately after their last one ships.
If TW101 and Bayonetta 2 bomb, it's unlikely that Nintendo will sign them for new projects, so they will have to search elsewhere for a publisher. They may have even already been doing such for the TW101 team if Nintendo indicated they weren't going to sign them for another project, but we likely won't find out until at least a year or more after it launches when Kamiya's next project is finally unveiled.
Platinum's biggest risk is that they run out of publishers who want to sign them if their games keep bombing, because signing them becomes a bad business decision. However, the individual bombs themselves don't directly hurt the company in the sense of "Bayonetta 2 didn't sell well and now we're $30 million in the hole," since they never spent any of that money in the first place.