(2) i can always purchase another new transport/streamer to go with the Transporter's built-in DAC (via digital inputs?) when higher than 24/96 is supported
Yes, but the wireless transmission in the Transporter is asynchronous so the master clock jitter the AKM DAC see is very low, unlike the S/PDIF input where the master clock comes from the digital receiver and can be 100 times more, at least.
Since I believe AKM DACs are really special (and I use them in all of my products), there is no doubt that the AK4396 DAC in the Transporter is nice (although inferior to the latest 32 bit AKM top-line DACs, IMHO!). Of course, it is all implementation, so "everything matters". And we can't really blame AKM for introducing much better 32 bit DAC solutions after the Transporter was released.
Hope this helps!
Best,
Alex Peychev
www.aplhifi.com