I don't suppose there is ever one *correct* answer for all scenarios.
Your question probably raises more questions than answers:
Do you release different versions of a plugin at different times. For example, if your product has ten plugins, and you release a new version of the product, would you be releasing new versions of the plugins at the same time, on the same release cycle.
Or is it possible to release a plugin on a different release cycle than the product?
My first inclination would to have all the code related to a product (and it's plugins) all contained within one TeamProject. I would not have a separate Team Project for each plugin unless these plugins are shared across products.
VS ALM Ranger