re: Will the Saints keep 5 RB's on active roster?

Good question OP.

Here's my take on it per player:

AD: Roster lock. $3.5m guaranteed, he'd have to show he's fallen off the cliff to be cut.
Ingram: Roster lock. As much angst he receives, he's an above average NFL RB with both rush and some rec prowess.
Kamara: Roster lock. You don't rate a guy this high to add a new draft pick and cut him.
Lasco: Likely on roster unless someone else really emerges to impress.

Out:
Cadet: Lesser talent, role is surpassed by others.
Murphy: Anything he does is done better by other players and he's not a RB.

I look back at some of the best CSP teams (2006, 2009) where Saints made NFCCG and won Super Bowl.

In 2006:
Deuce had 244-1057-10 and 30-196-0 line
Reggie had 155-565-6 and 88-742-2 line

In 2009:
Bell had 172-654-5 and 4-12-0
PT had 147-793-6 and 39-302-2
Reggie had 70-390-5 and 47-335-3

In 2011 (Sproles):
Ingram had 122-474-5 and 11-46-0
PT had 110-562-5 and 50-425-1
Sproles had 87-603-2 and 86-710-7

In 2016:
Ingram had 205-1043-6 and 46-310-4
Hightower had 133-548-4 and 22-200-1

In 2017 I think the thought and breakdown is this:

AD: Bell in 2009, a few more recs (15-20) and 140-160 carries.
Ingram: PT in 2009, 150-175 carries, 40 recs.
Kamara: Bush/Sproles role with less max recs, 50-70 carries, 55-70 recs.

Basically you get your thumper, hybrid and joker and it sets up nicely. I only wish TE position was more of a known. Would love that high baller go up and grab it in EZ to pair with MT and the underneath game.