Here we go again
In general, no, you are not both required to have a FP+ reservation to get a Rider Switch pass.
That was true before as well, but there were rare CMs who believe that everyone should be required to have a FP, and would trade a FP for the RS pass (since the RS pass was good for up to three people, it was sort of a 3-for-1 trade), but there was no actual operational policy that said it was required. And it was VERY rare, but reports persisted.
With the advent of FP+, nothing appears to have changed, but I think it is harder for these "rogue" CMs to trade the RS pass for the FP+, since the FP+ is electronic now.