Mark Ross (Producer) 1 confirmed:
Flakes (2007) (Confirmed by T!M as Mark Ross ("Produced By"))

Mark James Ross (Make-up) 2 confirmed, (0 unconfirmed, 3 invalid):
Guardians of the Galaxy Vol. 2 (2017) (confirmed by huskersports)
Life as we know it (2010) (confirmed by Nosferatu as uncredited and reverified by Hotm@iler with regards to DVD release.)
Insurgent (2015) (confirmed by AiAustria as invalid credit name)
The Walking Dead (2011) (confirmed by AiAustria as invalid credit name)
Watchmen (2019) (confirmed by huskersports)

Mark Ross (Make-up) (2 unconfirmed), (8 confirmed):
The 5th Wave (2016) (confirmed by JOHNNYV)
From Dusk Till Dawn: Season Two (2015) (confirmed by Nosferatu for episodes 3-5)
Avengers: Endgame (2019) (confirmed by huskersports)
Avengers: Infinity War (2018) (confirmed by huskersports)
Insurgent (2015) (confirmed by AiAustria)
Blue Ruin (2013)
Fear The Walking Dead: Season 4 (2018) (confirmed by Nosferatu)
Rites of Spring (2011)
The Walking Dead (multiple seasons) (Season 2 confirmed by AiAustria)
Hell Fest (incorrectly titled as Hellfest) (2018) (confirmed by Hotm@iler as SPFX Make-Up. Incorrectly credited as Executive Producer in credits)

Mark Ross (1966) (Rapper/Composer) (5 confirmed):
The 2 Live Crew: Greatest Hits DVD (Clean) (as Brother Marquis) (confirmed by Hotm@iler)
The 2 Live Crew: Greatest Hits DVD (Explicit) (as Brother Marquis) (confirmed by Hotm@iler)
Bring It On (2000) as Song Writer (confirmed by Nosferatu) (note: credits need to be removed from the profile, since this song is not written for the movie).
New Jack City (1991) as Song Writer (confirmed by Nosferatu)
Friday (1995) as Song Writer M. Ross (confirmed by bigdaddyhorse)

Mark Ross (Executive Producer) (1 unconfirmed):
Hellfest (2018)

Mark Ross (Actor) (1 confirmed):
Tapped Out (2014) (confirmed by Hotm@iler)

Mark Ross (Actor) (2 confirmed):
Nuclear Secrets (2007) (aka Spies, Lies and the Superbomb) (confirmed by Nosferatu on Episode 3)
Rebels and Redcoats (2003) (confirmed by Nosferatu on Episode 4)

Mark Ross (Producer) (2 confirmed):
Pantera - 3 Vulgar Videos From Hell (1999) (confirmed by Hotm@iler as Executive Producer)
Curfew (1989) (confirmed by Hotm@iler as Music Producer).

Please note: See original post, we are talking here about several other Mark Ross guys as well.

Mark Ross (Producer) 1 confirmed:
Flakes (2007) (Confirmed by T!M as Mark Ross ("Produced By"))

Mark James Ross (Make-up) 2 confirmed, (0 unconfirmed, 3 invalid):
Guardians of the Galaxy Vol. 2 (2017) (confirmed by huskersports)
Life as we know it (2010) (confirmed by Nosferatu as uncredited and reverified by Hotm@iler with regards to DVD release.)
Insurgent (2015) (confirmed by AiAustria as invalid credit name)
The Walking Dead (2011) (confirmed by AiAustria as invalid credit name)
Watchmen (2019) (confirmed by huskersports)

Mark Ross (Make-up) (0 unconfirmed), (10 confirmed):
The 5th Wave (2016) (confirmed by JOHNNYV)
From Dusk Till Dawn: Season Two (2015) (confirmed by Nosferatu for episodes 3-5)
Avengers: Endgame (2019) (confirmed by huskersports)
Avengers: Infinity War (2018) (confirmed by huskersports)
Insurgent (2015) (confirmed by AiAustria)
Blue Ruin (2013) (confirmed by Nosferatu)
Fear The Walking Dead: Season 4 (2018) (confirmed by Nosferatu)
Rites of Spring (2011) (confirmed by Hotm@iler)
The Walking Dead (multiple seasons) (Season 2 confirmed by AiAustria)
Hell Fest (incorrectly titled as Hellfest) (2018) (confirmed by Hotm@iler as SPFX Make-Up. Incorrectly credited as Executive Producer in credits)

Mark Ross (1966) (Rapper/Composer) (5 confirmed):
The 2 Live Crew: Greatest Hits DVD (Clean) (as Brother Marquis) (confirmed by Hotm@iler)
The 2 Live Crew: Greatest Hits DVD (Explicit) (as Brother Marquis) (confirmed by Hotm@iler)
Bring It On (2000) as Song Writer (confirmed by Nosferatu) (note: credits need to be removed from the profile, since this song is not written for the movie).
New Jack City (1991) as Song Writer (confirmed by Nosferatu)
Friday (1995) as Song Writer M. Ross (confirmed by bigdaddyhorse)

Mark Ross (Executive Producer) (1 unconfirmed):
Hellfest (2018)

Mark Ross (Actor) (1 confirmed):
Tapped Out (2014) (confirmed by Hotm@iler)

Mark Ross (Actor) (2 confirmed):
Nuclear Secrets (2007) (aka Spies, Lies and the Superbomb) (confirmed by Nosferatu on Episode 3)
Rebels and Redcoats (2003) (confirmed by Nosferatu on Episode 4)

Mark Ross (Producer) (2 confirmed):
Pantera - 3 Vulgar Videos From Hell (1999) (confirmed by Hotm@iler as Executive Producer)
Curfew (1989) (confirmed by Hotm@iler as Music Producer).

Please note: See original post, we are talking here about several other Mark Ross guys as well.

Based on all confirmed and invalid credits we have quite some data.

However, since there are too many different men with the same name and still only one of them with a verified BY, we can't determine which will be the common name.

The make-up guy is credited as Mark Ross and also credited as Mark James Ross.
Problem is that the majority of credits belong to the short name variant, otherwise we could directly have used the other longer name as the common name to distinguish at least two people.

I don't have anything against the longer name either, but I like to know what you guys think.

N.B. Even when we are trying to distinguish these, then we still have 4 other people of which we also don't have a BY and all have the same name.