1) Define 'safe'......Alliant says a 115g JHP at 1360fps using Blue Dot, Winchester has same bullet at 1340fps with WAP, Hodgdon has a 115g XTP at 1314fps with HS6, and Vihtavuori shows a 115g XTP at 1420fps using 3N37.
2) Best is nebulous, but of your three stick with Unique and Blue Dot.
I like WAP best, followed by V3N37 and Power Pistol.
3) Any dies. I like the Lee seat die because it's so easy to change OAL.
Finish using a Lee Carbide Factory Crimp die.
4) W-W or R-P new cases are both good. So is Starline.
Hope this helps, and start low and work up.
"All my ammo is factory ammo"