Howdy
I shoot lots and lots of Black Powder in CAS. There is no such thing as too much grease. But there is such a thing as a grease which is not compatible with Black Powder. With the wrong kind of grease, you can get a hard fouling that is difficult to scrub out of the bore. But with a good BP compatible lube, like SPG, the more lube, the more it helps keep things rolling. There are also lots of home made concoctions. I used to use a 50/50 mix of Crisco and beeswax.
The 1858 Remington is particularly difficult to keep rolling with Black Powder. I have two of them. But it is not because of the character of lube, it is because the front of the cylinder is flat and there is no raised bushing to deflect powder fouling blasted out of the barrel/cylinder gap away from the cylinder pin. Fouling quickly builds up on the pin and causes binding. I have shot all kinds of BP guns, and the 1858 Remmie is the worst to keep rolling, because of the lack of a cylinder bushing.
As far as preventing a chain fire, lube really is not very effective for that. Back around 1968 when I bought my first C&B revolver the standard advice to avoid chain fires was to slather Crisco over the balls. What really happened was the Crisco in the chamber next to the one that was being fired melted, from the hot blast out of the barrel/cylinder gap. A thin runny layer of melted lube is not a very good spark arrestor.
The best spark arrestor is felt wad between the ball and the powder. Yes, you should always use an oversized ball, and a nice ring of lead should always be shaved off. But if the ball is misshapen, or dented, and shaving the ring does not obliterate a void created between the surface of the ball and the chamber wall, you have a nice path for an errant spark to follow down to the ball. And yes, I have experienced a chain fire, it will really wake you up. But with a nice felt wad about 1/8" thick between powder and ball, even if a spark gets past the ball, it will not reach the powder.