So, hoping to increase my knowledge a bit on several somewhat popular hulls:

The Prospector, the Penobscot and the Canadienne. I've seen multiple brands with "Prospectors" but only OT for the Penobscot and the Canadienne.

I am under the impression that the first two have enough rocker to be used on rivers in addition to lakes - is this correct? How are they different?

For prospectors, is there much design variation from one manufacturer to the next?

I know not much about the Canadienne.

Any insights appreciated!

Prospector was a Chestnut Canoe Company(NB,CA) model built originally in wood/canvas. It was the go-to canoe for northern Canada travel for decades(big lakes and pushy rivers). Current models vary a lot. Bunch of rocker, a shallow arch cross section and deep, usually 14 inches. Its twitchiness surprises folks used to flat bottomed hulls, but is a very seaworthy design in big waves. Probably the best of the three for river tours as it has the most rocker, but it is a fine lake country canoe. I think Souris' prospectors come pretty close to the originals. I believe you can still get a wood canvas one made on some of the original Chestnut mold which were dispersed when the company closed in the mid-1970s.

Penobscot is a more modern design and a good all around canoe. Enough rocker to run rivers and travels well on lakes. I believe it also has a 14 inch depth, making it comfortable in big waves. It won a lot of downriver races when it first came out. If I was looking for a fleet of tough canoes for a youth program, this would be on the list.

The Canadienne was designed by Ralph Freese of Chicagoland Canoe Base. A v-bottom that flattens out to shallow arch in the center. I think Ralph drew on the designs of William English, an Ontario builder of wood canoes from turn of the last century. His Model #20 is very similar, but only 16 feet. A real cool old-fashioned design that is comfortable touring. I would not recommend it for river touring that has rapids. Only available in fiberglass or kevlar.

Thank you; my ignorance has been considerably reduced! Very much what I was hoping to learn, and then some.

Do not believe any design called 'prospector'. That original design has been duplicated,manipulated, stretched,shrunk, shallowed, and deepened to the point that it is definitely not the original.its an abused name for a canoe. And the original prospector is not a very good design anyway.
Tom