Looks like your TV has both optical and line level outputs (RCA connector).
So, depending on the specifics of each Adapter, you can probably hook one to the optical output and the other to the line level unless you are using one or both already for something else. I would suggest you use optical if available. My Oticon TV Adapter 3 has an optical input AND an optical output - if either the ReSound or Phonak TV adapters are similar, you could connect the adapter with both input and output to the TV and the second adapter to the digital output of the first.
Searching the Resound site, it looks like the ReSound TV Streamer 2 accepts both digital optical and line level inputs (RCA and mini jack). However, apparently no digital optical output.
Looks like the Phonak TV connector has both digital optical input and analog (3.5 mm jack). Apparently no digital optical output.
You could possibly find an active digital optical splitter to allow both Adapters to use the single optical output from the TV - I have no experience doing that but it should work if the splitter is a decent quality unit.
With my old Panasonic flat screen TV, muting the TV sound output has no effect on the digital output. If you Sony TV is similar, one user should be able to listen to streamed sound with the TV muted and the other HA user could watch in silence.