In Season 1, Tony was a Capo. As you said, Junior was made the nominal Boss by the episode "Pax Soprana", but still, Junior was in a position where he made most of the family decisions (Tony just altered them). For example, Junior wanted to tax Hesh, he taxed Hesh. Tony was only able to manipulate it slightly and lower the Tax figure.
Silvio was most likely a soldier in Tony's crew. The capos of the family at the time were Tony, Junior (before Jackie died), Jimmy Altieri, Ray Curto and Larry Boy Barese. Oddly, there was no Acting Capo for the Aprile crew.
When Junior is named Boss, Jackie's title card is removed and Junior's is replaced as Boss. Tony remains a Capo according to the FBI. Junior had his own underboss, Joseph "Beppy" Sasso, who we didn't see much of because he was sick.
This is how the Administration of the Family looked after Junior was made Boss:
Corrado "Junior" Soprano
Joseph "Beppy" Sasso
Michael "Mikey Grab Bag" Palmice
Now, the Administration of the Family is:
Chris is Capo of the crew that was once Paulie's crew and Tony's before him.
Johnny Boy Soprano