Alright, I guess it’s time for me to math this out. Now for simplicity, I’m going to ignore everything other than com, and skills (will do no stacks and full stacks for comparison, as well as comparing other conditionalities). The reason for ignoring other type of gear is that anyone can use that gear, so the only differences come from the coms and skills. As a result the listed bonuses are just from com+skills (other sources would typically add to it).
Accuracy:
-Axton: +46% (Lawful ? Ranger com, 11/5 Ranger)
-Gaige: up to +97% (+32% from Prodigy com, with Discord specd) [+up to 65% from Discord; -1.75% per Anarchy stack remaining]
-Krieg: +145% (+35% from Lawful ? Barbarian com, with +6 Fire Fiend) [+110% from being on fire; 11/5 Fire Fiend]
-Maya: +35% (Lawful ? Cleric)
-Salvador: +81% for AR, +30% for other gun (Raider com; 5/5 Divergent Likeness; Gunzerking with an Assault Rifle and another gun); can always get at least: +66% {while gunzerking with two guns of different types} (Pragmatic Devastator; 11/5 Divergent Likeness); +35% {otherwise} (Lawful Monk com)
-Zer0: +90% {+195% when Hip-firing Sniper Rifles} (Sure Shot com, 11/5 Precisi0n; {5/5 At 0ne With The Gun})
Action Skill Cooldown Rate:
-Axton: +100% (Leg. Engineer; gives +50% and 10/5 Resourceful)
-Gaige: +107% (Leg. Mechromancer; 10/5 20% Cooler)
-Krieg: +440% from taking health damage [+220% from taking shield damage] {+0% without taking damage} (Rampaging Slab; 11/5 Fuel the Rampage)
-Maya: +83% (Leg. Siren; 5/5 Quicken)
-Salvador: +76% (Leg. Gunzerker; 5/5 I’m Ready Already)
-Zer0: +54.5% after killing an enemy for 7 seconds [+47% otherwise] (Leg. Hunter; 5/5 Grim)
Critical Damage:
-Axton: +65% (? Evil Ranger; 11/5 Ranger)
-Gaige: +54% (? Evil Necromancer)
-Krieg: +54% (? Evil Barbarian)
-Maya: +79% (? Evil Cleric; 5/5 Mind’s Eye)
-Salvador: +89% (? Evil Monk; 5/5 Quick Draw, 5/5 Lay Waste)
-Zer0: +6261% with sniper rifle and 999 CA stacks [+267% without CA stacks] {both cases require kill in last 7 seconds and enough ADS time to get full KC; without KC: 227%, without kill in last 7 secs: +167%, without either: +127%} (Leg. Killer; 10/5 Headsh0t, 10/5 Killer, 10/5 Vel0city, 5/5 Kill C0nfirmed)
Fire Rate:
-Axton: +184% with non-elemental gun and kill in last 7 seconds {+169% for elemental gun} [without kill in last 7 seconds: +52% with NE gun, +37% otherwise] (Heavy Gunner; 11/5 Metal Storm, 5/5 Duty Calls, 5/5 Ranger)
-Gaige: +177% for latter half of magazine with Discord [+55% for first half] {without Discord: +162% for latter half of magazine, +30% for first half} (Superior Punk; 11/5 The Better Half, Discord)
-Krieg: +255% with 20 Elemental Elation stacks and shield depleted (Razed Toast; 5/5 Embrance the Pain, 11/5 Elemental Elation); without EE, best is: +77% with shield depleted (Pain Meat; 11/5 Embrace the Pain), without either, best is: +31% (Chaotic ? Barbarian)
-Maya: +110% with an enemy Phaselocked (Scheming Cat; 11/5 Wreck); best without Phaselocked enemy: +35% (Chaotic ? Cleric)
-Salvador: +248% having reloaded recently, killed an enemy in last 7 secs, have been Gunzerking with triggers held down for long enough, and shield is depleted (Leg. Titan; 10/5 Locked and Loaded, 5/5 Lay Waste, Keep Firing…, 10/5 All Out of Bubblegum) maximum unconditional fire rate: +33% (Chaotic ? Monk)
-Zer0: +57% while shield is depleted (Chaotic ? Rogue; 5/5 Fearless); without shield depleted: 35% (Chaotic ? Rogue)
Gun Damage:
-Axton: +302% with a non-elemental Assault Rifle, a kill in last 7 secs, shield depleted, turret deployed, in FFYL (purple Assault or Frontline Rifleman; 10/5 or 9/5 Onslaught, 5/5 Crisis Management, 9/5 Impact, 9/5 or 10/5 Battlefront, 5/5 Duty Calls, 5/5 Ranger, and 5/5 Last Ditch Effort); Without AR: +255%
-Gaige: +1050% with 600 Anarchy (Leg. Slayer of Terramorphous; 9/5 Preshrunk Cyberpunk); +756% with 400 Anarchy and +56% with 0 Anarchy (Leg. Anarchist) Can achieve: +1106% by pre-stacking to 600 with Slayer then swapping to Anarchist
-Krieg: +700% with a shotgun and 100 Bloodlust, 20 Salt the Wound, and being on fire (Blood Blister; 11/5 Blood Bath, 5/5 Salt the Wound, 5/5 Pain is Power) minimum unconditional: +55% (Power Toast; 11/5 Pain is Power) {gives +110% when on fire}
-Maya: +248% with an SMG against enemy with over 50% health [times 1.6 due to Wreck] (Leg. Cat; 10/5 Accelerate, {10/5 Wreck}, 10/5 Reaper)
-Salvador: +118% with pistols at very low health {ignoring all multiplicative skills} (? Renegade; 5/5 Keep It Piping Hot, 5/5 Just Got Real); +113% with non-pistols at very low health (Savage Beast or Savage Devastator; 5/5 Keep It Piping Hot, 11/5 Just Got Real)
-Zer0: +5176% {an additional 2% while in deception is possible w/ 1/5 Innervate, but there are not enough skillpoints to get any more from that skill} with a SR, 999 CA stacks, shield depleted, 5 Rising Sh0t stacks, killed an enemy in last 7 secs, and are moving; without CA: +181% with SR {an additional +10% while in Decepti0n} (Leg. Sniper; 10/5 Vel0city, CA, 5/5 Fearless, 5/5 Rising Sh0t, {1/5 Innervate}, 5/5 F0ll0wthr0ugh, 5/5 Like the Wind)
Health Regeneration:
-Axton: +6% max health and +11460.1 [max health is getting +70% and +352619] shield fully charged, damaged an enemy in last 3 seconds (Leg. Pointman; 10/5 Able, 5/5 Ranger, 10/5 Healthy, 5/5 Forbearance)
-Gaige: +7.2% max health [max health is getting +20% and +246833] magazine fully loaded, consuming Anarchy stacks with Discord (Patient Sweetheart; 11/5 Cooking Up Trouble, Discord)
-Krieg: +15427.1 (any Meat com) [Most of Krieg’s sustain is considered healing, not regeneration]
-Maya: +11% max health {with enemy phaselocked} and +4% missing health [max health is getting +15% and +352619] (Angelic Matriarch; 5/5 Restoration, 11/5 Elated, 10/5 Sustenance)
-Salvador: +4.9% max health {4.4% of which is for 5 secs from taking dmg} +4% missing(?) health [max health is getting +20% and +324409] (Altered Beast; 5/5 Hard to Kill, 5/5 Ain’t Got Time to Bleed, 11/5 Sexual Tyrannosaurus)
-Zer0: +4% max health {while in Decepti0n} [max health is getting +30% and +324409] (Leg. Slayer of Terramorphous; 5/5 Innervate, 10/5 Ir0n Hand)
Magazine Size:
-Axton: +147% with AR, +97% with non-AR (True Neutral Ranger; 5/5 Overload, 11/5 Ranger)
-Gaige: +86% (True Neutral Ranger; 0/5 Smaller, Lighter, Faster, which means at most 1 point in Ordered Chaos tree)
-Krieg: +637% with 100 Bloodlust Stacks and 20 Elemental Elation Stacks (Leg. Psycho; 10/5 Blood-filled Guns, 5/5 Elemental Elation); best without stacks: +86% (True Neutral Barbarian)
-Maya: +106% (True Neutral Cleric; 5/5 Foresight)
-Salvador: +111% (True Neutral Monk; 5/5 Filled to the Brim)
-Zer0: +86% [an additional +5 magazine size for Sniper Rifles] (True Neutral Rogue; 5/5 At 0ne with the Gun)
Maximum Health:
-Axton: +70% and +352619 (Leg. Pointman; 5/5 Ranger, 10/5 Healthy, 5/5 Forbearance)
-Gaige: +20% and +324409 (Leg. Slayer of Terramorphous; 5/5 Potent as a Pony)
-Krieg: +110% and +352619 (Beef Slab; 11/5 Feed the Meat)
-Maya: +15% and +352619 (Matriarch; 5/5 Restoration)
-Salvador: +44% (Hulking Tank or Hulking Titan; 11/5 Hard to Kill) {beats out Beast com w/ Rough Rider}
-Zer0: +27% and +324409 (Leg. Slayer of Terramorphus; 9/5 Ir0n Hand)
Numbers should be correct now (checked com numbers against max stat spreadsheet at OP8).