IMO tony did't have that good relationship with junior that time (you can even see in season 1 that they cannot settle a small beef between their crew's).
but why sending pussy ? i have no idea, you right its really seems weird.
But remember, in Season 1, Jackie is dying. There's no real leader keeping the two of them in line. Whereas in '95, Jackie was healthy, had the backing of the Family, and would not hestitate to kill Junior if Tony couldn't get him under control. Junior would've understood this, and much quicker if it was Tony coming down and saying "Look, Uncle Jun...You gotta settle this shit with Jackie. You wanna wind up popped?"
Pussy and Junior had no relationship, no history, Pussy was one of Johnny's guys - why the fuck should he trust Pussy to arrange a sitdown? How does he know Puss isn't setting this sitdown up for Junior to be popped?
