The answers to all of your questions are easy to find... I believe all the Defensive draft picks were 2011 or beyond, so Elway guys.
https://www.pro-football-reference.c...015_roster.htm
2015 Roster
Offensive starters drafted by Denver = 5
Defensive starters drafted by Denver = 5 + 2 UDFA's that never played for another team prior, so those count all the same.
22 starters and 12 drafted/UDFA starters... 10 va FA.
Those 10 = Manning, Sanders, O Daniels, E Mathis, L Vasquez, B Marshall, Ware, Talib, Ward
Ware, Talib and Ward with Wade made them badass. That is what FA is for...
Carry on.