With my limited knowledge I will offer some thoughts. It's free so take it for what it is worth..

#1. The 457 bullet mould is probably for casting bullets for your pistols. The RB probably stands for "Round Ball" which is the favored projectile for percussion pistols. And the 457 probably stands for the diameter in inches of the round ball that is produced by the mould. In the only percussion pistol that I own 0.457" round lead balls are reccomended/required. I have no clue as to what 476 means.

#2. A wild guess. If your Midd Conn pistol is a smaller bore, like 0.36" or less the cloth pieces could possibly be used as patches for the bullet. Do they feel like they have anything on them? Bullet patches are lubed with many different compounds. The loading procedure is pour measured quantity of powder down the bore, place patch over muzzle, and push bullet down on patch and into bore. This may require a tool known as a "short starter". Then a ramrod is used to finish the load by firmly seating the bullet on the powder.

#3. If the powder is dry it will still work. If it is real black powder and even if it got wet at some time the powder can be allowed to air dry and it will still work.

#4. Could be patches used for cleaning.

Others may chime in and correct any inaccuracies that I have mentioned.

NEVER EVER USE SMOKELESS POWDER in any of these pistols.