Major The payload for EiCreateTender has no counterparty so the assumption must be that it is only sent to those counterparties that the invoker selects and that only those that receive it can respond. Correct?
YES
Distribute Quote and Distribute Tender would be sent to all parties in a location. Correct?
MAYBE. Distribution within a site is dependent on the implementation and how the parties have been identified/Registered. They would go to a web services (WS-Addressing style) endpoint or other locations, e.g. geospatial (all entities in a geospatial polygon that defines Marin county, for example). There is no assumption that there's one Party in a relationship at a particular endpoint/area.
Distribute has no expectation of a response or acknowledgment. Do all other messages require acknowledgment?
YES
It also would seem that Create Tender would have no expectation of a response other than perhaps acknowledge
NO. The response (corrected to use ResponseType in wd25wip1 model and schemas) returns the offeree (to be corrected to Tenderee per another item), the ResponseType, and the EmixBaseType that's created (basically the full Tender; EmixBaseType allows any derived type to be that payload).
It seems that the Distribute operation has the distinguishing feature that the set of parties the payload to send to is based on a geographic area or location whereas the create operation is sent to specific parties with no geographic limitation expressed. Both have no expectation of a response. Correct?
NO. Distribute operations have no expectation of a response, although one can be made (this is more a fan-out/server load issue, though Distibute* is there for broadcast with other specifics such as geospatial area. CreateTender expects a response (EiCreateTenderPayloadType) as described above.