I'll wait on your other post, but provided the album artist/album grouping has not been fiddled with and the Trk# field was ripped/tagged correctly, there are 3 ways that I can think of that JRiver will not play an album's tracks in numerical sequence
1) inadvertantly the shuffle button on top right under the player window, above the main panel, is "on"
2) you have selected and linked the tracks - these can be reordered and will be remembered (doubtful, sort of an advanced functions, the "linking" can be cleared)
3) you are not using JRiver as a front-end but are launching playback from Windows explorer AND the file name template when you ripped did not put the track number first, so windows didn't sort them in order. eg. 1_Anyhow_Let Me Get By_Tedeschi Trucks Band.flac vs. Anyhow_Let Me Get By_Tedeschi Trucks Band_1.flac
Linking 2 zones for simultaneous playback, can be tricky. It is not clear, but it sounds to me like you are using an Oppo 105 as a DLNA renderer. If possible you should use it for audio just as an external DAC, using JRiver as a renderer. Some functionality doesn't work as well (or not at all depending). I'm not even sure if you can link multiple external DLNA renderers so I would solve your sequential playback to one zone first before attacking the issue mentioned in the other post.