All, thanks for the feedback!
1- Encrypt is now available in Outlook Windows desktop April release monthly release Version 1804 (Build 9226.2114). See here for more details: https://technet.microsoft.com/en-us/office/mt465751.aspx?f=255&MSPPError=-2147217396.
2- Encrypt is currently not available in Outlook Mac. It is currently being built. However for any issues with Do Not Forward in Outlook Mac, please contact Support.
3- @Zach, OMEv1 is still supported for tenants that had previously set it up.
There is currently no way for customers to remove encryption for OMEv2 for inbound mail. We do not plan to support this feature.
4- @Gloria, we are aware of the ask to have the AIP Encrypt only label. The AIP team is chasing this.
5- Jason, we have recently heard this issue for B2B mail and are working to fix it. I don't have an eta yet.