DSF (DSD) or DFF (DSD) can be streamed multichannel over DLNA but pretty sure it won't stream an ISO. Oppo removed that functionality a long time ago, so you'll need to extract the individual tracks. If you ripped the iso's then you shouldn't have issues doing this - except for time it will take and hard drive space needed
To stream individual DSF or DFF:
Configure a media server and configure to stream as original format. Associate that server with the Oppo when it shows up in your network list under playing now. When you play the file back Oppo will indicate it's SACD playback.
Only thing it won't do over network is provide gapless for anything. For that you need to play from a network drive, or hard drive connected to the unit vis USB port. Edit: It won't do gapless DSD at all. For that what I do is rip the SACD ISO to one large .dff with a cue sheet. When streaming the .dff via JRiver the CUE information displays correctly, but it's kind of useless because when streaming you are not able to select individual tracks. It's an all or nothing playback.
The CUE file works fine when used with Oppo's app for USB connected drive playback.
Funny that you are going from exasound to JRiver. I'd prefer to go the other way, but it's not worth spending the money on that DAC. My 205 gives me most of what I want - except the gapless playback over DLNA. And it sounds great.