I'll refrain from comment on Paul Revere's character, but The Penobscot Expedition was peripherally about Native American Lands.

The expedition was actually to dislodge a recently built fort established by the British. The fort, called Fort George or Fort Penobscot, was built in what is today Castine, Maine (It's actually still extant- although the current remains probably owe more to the British reoccupation of the site during the War of 1812) on Penobscot Bay. The fort was built the early part of 1779 by British soldiers from Halifax, Nova Scotia. The British hoped establish the Fort as a naval base to get timber for the navy, block Continental attempts to support potential rebellion in Nova Scotia, and to hopefully serve as a refuge for loyalists fleeing the New England states.

Maine was, at this point, still part of Massachusetts. Massachusetts responded by calling out a large force of militia, using its own navy, the Continental navy, and some privateers to assault the newly established British fort. This whole force was placed under the command of Dudley Saltonstall of the Continental Navy as naval commander, and Solomon Lovell of the Massachusetts Militia as commander of the ground forces. Paul Revere was Lieutenant Colonel in the Massachusetts Militia, and placed in charge of the expeditions artillery.

The objective of the expedition was to destroy British fort, and remove any potential threat of British naval base in the area- it did not include dispossessing the Penobscot of their land.

I won't recount the whole battle, but it had been called the United State's worst naval defeat before Pearl Harbor. It was a confused disaster for the Continental and militia forces, resulting in massive losses of ships, arms, and men. That resulted in several court martials- including one for Paul Revere (You can read some of the original documents here).

Essentially, Paula Revere was accused of cowardice and disobeying orders. He was found guilty of having disobeyed orders, and apparently censured but not cashiered from militia, or reduced in rank. Revere's service in the Penobscot Expedition ended his sort career as a military officer during the American Revolutionary War, however.

All of this being said, however, the battle did take place on land originally owned and still claimed by the Penobscot people. There was some worry that a British fort in the area would sway the Penobscot from their friendly position to the United States. Not that friendly disposition stopped their land from being expropriated and settled by Anglo-American settler after the war, however.

Would I say the Penobscot Expedition was aimed at displacing the Penobscot people from their lands? No- I think that's misunderstanding of the goals of the expedition. Did the Penobscot eventually have their land stolen by the United States? Yes, but not as a result of the Expedition.

As for Paul Revere's role in it, I don't think I would say he had a high-level role in the Expedition. He mostly played a contributing role to the military disaster that was the Penobscot Expedition.

Works cited:

Buker, George E. The Penobscot Expedition: Commodore Saltonstall and the Massachusetts Conspiracy of 1779. 2002.

Goold, Nathan, and William Moody. 1899. "Colonel Jonathan Mitchell's Cumberland County Regiment. Bagaduce Expedition, 1779". Collections and Proceedings of the Maine Historical Society. 10: 52-80.

Williamson, Joseph. 1892. "The Conduct of Paul Revere in the Penobscot Expedition". Collections and Proceedings of the Maine Historical Society. 3: 379-392.