I would definitely put the best of the BPP below Mao in part because that's what they would say themselves -- that the Chinese communists and Mao specifically were a model and an aspiration to them.

I don't think it makes that much sense to put them below Sankara though, because Sankara was the face of someone else's military coup, tried to do socialism for 5 years, accomplishing some lasting reforms but evidently not really fixing the basic issue of the proletariat not controlling the state, and then was killed via military coup by the same guy who organized the first one and had his attempt at a socialist government washed away.

It's true that Fred Hampton, etc. failed to topple the US government, but they weren't coming from positions of already having significant power in the government and military, and actually did grassroots organizing against the most powerful state in world history before its domestic intelligence agency, which itself described Hampton as "Messianic," assassinated him.

As a demonstration of what Marxists should do in a capitalist state, the better Panthers are a much stronger example, but Sankara gets points for enacting some good reforms during the brief period when the military allowed him to be the face of their power. Tier lists in this context are a crass joke, but I think if the scale is so broad that with 7 tiers Pol Pot is somehow even mentioned, putting Hampton and Sankara in the same tier seems fair to me.