It looks right to me except for the 84-26 that I can't see. The 8100 PCPro won't let me open the file. I can open it in 9100 PCPro and it prompts me that it is the GE market and opens the file and converts it but the 9100 shows 84-26 as the default settings and not the IP address you have assigned. I suspect this is because the processor that has the VoIP DB gets removed in the file conversion.
I did forget that this is an 8100 and the port forwarding is slightly different in 84-26:
Gateway 1 will require ports 10020-10051 forwarded.
Gateway 2 will require ports 10052-10083 forwarded.
Gateway 3 will require ports 10084-10115 forwarded.
Gateway 4 will require ports 10116-10147 forwarded.
Gateway 5 will require ports 10148-10179 forwarded.
Gateway 6 will require ports 10180-10211 forwarded.
Gateway 7 will require ports 10212-10243 forwarded.
Gateway 8 will require ports 10244-10275 forwarded.
Each VoIP call will use a pair of ports starting at 10020 and 10021, the next call will be 10022 and 10023. These ports are your transmit and receive for the audio of the call. If you only have 10020-21 forwarded and an IP call is already taking place on the system that could account for no audio since those two ports would already be in use.
If none of that works, you could try unchecking NAT in 10-33, removing the 10-12-07 address (shouldn't matter with 10-33 unchecked but we're being certain) and enabling SIP transformations on the SonicWALL. You will need to add 5070 as an additional transformation port in the SonicWALL VoIP section since the uMobility does not use the default 5060 but uses 5070 instead. This isn't supported by NEC, but I have done it in the past successfully.