1) I don't use a progressive press. But there's a thread recently on that issue.
2) Not a chance! Modern guns are made to withstand smokeless pressures, which far exceed any amount of BP you can stuff into the same space.
3) Hardly a "pain". It is a bit more involved than cleaning up after smokeless, but takes me maybe 45 minutes for 4 guns. Watch Mike's videos, they're great.
4) What do you mean by "safe"? I've never even heard that brought up before, so I can't comment. I will say this - I switched to real BP after shooting Pyrodex for a year, and I'll never go back. The smoke off of Pyrodex was much more acrid and smelly. BP smoke is smooooth.
5) A manual? Here's all you need for CAS -
A) Load cases with BP, leaving enough space for bullet minus 1/8 to 1/16 inch to compress the powder.
B) If you don't want a full-power load, use a filler such as oatmeal, cornmeal, grits or similar, to fill in airspace.
C) Use LOTS of BP lube. Examples - BigLube molds, Lyman molds, or some people - myself included - use felt wads soaked in lube. (I make my own, but you can buy Wonder Wads for lots more $$$). Bullets from Lee molds, IMO don't carry enough lube for BP. No experience with others. DO NOT use smokeless lube, use a BP-specific lube. You can buy it or make your own.
D) Use a nice solid crimp.
E) Enjoy!
Now, BPCR (or any long-range shooting) is an entirely different beast, but for CAS or plinking, the above is really all you need to know.