The TokenTalk NB Card does not support 16MB Token Rings, and we are not aware of a product for the Macintosh that will connect directly to a 16MB Token Ring. Therefore, we are not able to suggest a solution for option #1.
For option #2, there is a possibility. IBM has software for a PC that provides source-level routing between two Token Ring networks (including routing between a 4MB and a 16MB network). Since TokenTalk supports source-level routing, the TokenTalk packets would be routed by this bridge. The name of this IBM software product is "Token Ring Bridge Program".
One possible configuration for the network you described is:
Put the Macintoshes on a 4MB ring. This 4MB ring would be connected to the 16MB ring via a PC with two Token Ring cards (one 4MB and one 16MB).
Routing to the Ethernet will be somewhat trickier. You could have another PC running the bridge program as described above. Connected to the 4MB side of this machine would be a Macintosh with a TokenTalk NB Card and an EtherTalk Card running the Apple Internet Router.
This configuration will route only AppleTalk packets onto the Ethernet. Some other device would have to be responsible for routing other protocols onto the Ethernet.