All of these are very good rectifier tubes and will handle 99% of the needs for all tube amps.
The "maximum" capacitance figure listed is the highest capacitance the rectifier tube should have connected directly to it's output. It is one of the considerations necessary when using rectifier tubes in amplifiers.
Often a Fender or simular amp has the first two capacitors wired in series - this reduces their value by half - such as, two 80 mfd caps in series is 40 mfd - ok with 5U4 and 5AR4, not ok with 5Y3
NOS means "New Old Stock" Old tubes than have never been sold or used. Ours are usually from military sealed boxes - leading to the next term:
JAN means "Joint Army Navy" made to very high quality standards for the military.