Apologies for the Necro Post, but I thought I'd go through the races, and then perhaps we could look for ways to balance them out.
As noted, the Atani have a +2 ability, a -3 ability, and glide, which I'd put at about +1. That puts them at a net +0 (or +1, if you want to count gliding the equal of flying).
I'm leery of upgrading them to full flight; the idea is more gliding, so let's keep that. Instead, let's give them either +1 parry (they're quick and nimble to avoid attacks) or +2 charisma (their free spirits make them easy company for other races).
Doreen. I'd put coup at about a +1 ability. Getting bennies is always nice, but the restrictions on the ability are kind of tough. If he gets the benny, he's definitely earned it. Racial enemy is a -1. This version of semi-aquatic gives most of the abilities of regular Aquatic. Call it +2.
I'd say on the whole they're pretty balanced. No need for a change.
Grael. Now, there's a large load of positives and negatives. -1 for All Thumbs. Blubber... Okay, call it +1 for the armor. +1 for the resist cold. We'll be generous and call it -1 for the vulnerability to heat. +1 total. -3 for Dumb. Semi-aquatic, we'll go ahead and call a +2. It's weaker than the doreen's version, but still stronger than the regular version, and we already gave them a -1 for a weaker version of heat vulnerability, so that kind of balances out. +2 for size. -1 for pace 4. +3 for strength.
Okay, so that puts us at +3. I'm loathe to add another ability to what's already a mechanical monstrosity, so let's go ahead and strike off a plus. I'd say go for the +1 armor from blubber. It still protects them from the cold, but weapons will go through it easily enough.
Humans are effectively +3 with the free d6 of masaquani in addition to their edge. However, that's there because of an unspoken disadvantage they have, insofar as the vast majority of inhabitants don't speak English, Spanish, or whatever their native language was. I'd put that as frankly neutral.
Kehana. They've got the full aquatic ability, so that's +2, balanced out by the -2 from dehydration. They have a slightly worse version of Habit (minor), but the effect is -2 charisma, which is a -1 ability. Racial enemy gives them -1. Their natural weapons are at a +1 (two sets, but they can still only make the normal number of attacks).
Net result is -1, so they're one of the ones Clint mentioned as being more unbalanced. One possibility that springs to mind is giving them poison to their natural attacks. That seems to fit into the image of cruel, vicious fish-men. Add in low-light vision (to help them spy things in the deep waters), and they should balance out nicely.
Kraken get both aquatic and dehydration, just like the Kehana, for a net 0. Natural Talent is +2. Another race that balances out nicely. No change here.
Masaquani just have Iconic. They effectively get a starting attribute of d6, which is +2. The fact that it's their only ability, for good or ill, makes up for the fact that they can put it wherever they like. Again, a well-balanced race.
Red Men next. -1 for All Thumbs. -2 for Clueless. -3 for Dumb. -1 for Outsider. +2 for Strong. +2 for Tough. And I'd say +2 for Tough as Nails. Yes, it's a legendary edge, and a free seasoned edge is +3. However, the effect is +1 toughness, which is a +2 ability. Frankly, getting it through Tough As Nails is worse than just a flat +1 to toughness, since it means they can't take the edge when they hit legendary. That puts them at -1 total.
Okay, so, we need to give them +3. Okay, so first, let's trim down the abilities they do get. Lessen Dumb to the -2 version. They're still at a disadvantage in the smarts field, but it doesn't hit them quite as bad. Tough as Nails simply becomes +1 toughness, no reference to the feat. No change to the net total, but they need every advantage they can get. Now, let's increase their Tough ability to the +3 version. Grael already have the "Really, absurdly strong" field covered, so let's make the Red Men the toughest sons-of-bitches on the seas. They're billed as being almost feral, so let's give them keen senses (hearing). That puts them at +2.
Scurrilans next. Pincers... It's a natural weapon, so +1. Two extra limbs, which would normally be +4. However, they inflict MAP on themselves. Call it +3. -1 because the pincers aren't capable of fine dexterity, for a total of +3. -1 for the charisma penalty. Keen Mind... Let's call it +1. +2 to knowledge rolls is nothing to sneeze at, but it's fairly limited in scope. Shell I'd say is roughly equivalent to +2 armor all over, with the caveat that it doesn't stack with regular armor. Call it +1. Telescopic eyes are roughly neutral (some nice bonuses, but those eyes are vulnerable).
So, +4 total. Hoo boy. Well, let's look at this. First off, let's look at what scurrilans actually look like. They're not humanoid. Not even close. Of all the races, they're most different. So, they're not going to be able to slip on just any armor. Any armor they wear has to be specially fitted to scurrilans. That's at least -1 right there. You can fold it into Shell to keep the stat block from being too monstrous. Next, let's look at their pincers. They have four useable limbs. However, two of those have no real manual dexterity, and the other two are very small. They're not going to be wielding weapons with the pincers. Give them a penalty to damage with melee weapons wielded with their small claws. Possibly limit them; they don't rally have the leverage to use, say, a warhammer with those claws. They're also not going to be able to use most two-handed ranged weapons. Longbow won't work well, and they probably won't be able to take the recoil from a blunderbuss or a musket. Call that a -1. That should bring them in line.
So, thoughts? Have I over-or-undervalued anything? Are any of the suggested changes too much, changing the flavor of the races too greatly?