Well it depends on how your whole event handing is configured..

E.g. we track participation in custom reports so we add another participation. This way we can see this participant on both reports (i.e. sponsors and tables)

We use a Hierarchy for Participation: Neither of which I use to track the 2 things you're tracking

Example: Sponsor, Donor, Guest, Vendor etc. Sponsorships and reservations are broken out further by using registration fees.

Committees we track using Constituent Attributes - not the actual event

Table Hosts is what I would name a Seating Group

NOTE: By making all committees Constituent attributes, it's easy to use the canned reports Directories for all committees across the board.

There are various fields within the registration record that could handle the following: solicitor, participation, status, and some other ones. The participation look up can handle only one value per registration. So, if you need to utilize more participant types, you could use attributes.