I was hired by Sun. Just before my start date, Oracle announced they would be buying Sun. I was worried, but it turns out acquisitions are pretty slow processes. There was months of waiting for government approvals, then months more before the culture really started feeling like "Oracle" instead of "Sun."
In short, there's a decent chance that anyone applying now could be on payroll for months or years before Visa actually meaningfully changes anything about Plaid's workflow.