Replacing the Balseraph Warrior with a Freak would be a neutral change, on average. Some games your Freak would be virtually worthless because of bad mutations (although you could still use it to drop a Freakshow in your starting city, or better yet in your second city); in other games it would be a combat monster. This would be the most balanced of the changes mentioned.
As for the rest, although they are flavorful changes I do not consider them balanced:
Replacing the Doveillo Scout with a Wolf would be a big disadvantage. A Wolf cannot see Spiders, does not have a bonus against animals, and does not get better results from tribal villages like a Scout. If you decided to execute an early attack on your neighbor your chances would be reduced, because the Wolf has a city attack penalty that Scouts do not have. The best use for this unit would be to construct a Wolf Pen, but you can't do that until you've researched Festivals and built a Carnival. Until then the unit is dead weight (in comparison to the Scout it replaced).
Replacing the Hippus Scout with a weak Horseman (by which I assume you mean a Horseman with the Weak promotion) would be an advantage. The Horseman is unable to see Spiders and would not get better results from villages, but would move twice as fast as a Scout - and so would on average be able to collect twice as many villages as a Scout before animals began to appear (this would be a more pronounced factor at longer game speeds). It would be very powerful in combat: Str 3, move 4, 1 first strike, 35% withdrawal, +40% vs archers - much stronger than the Warrior others get.
Replacing the Sheaim Warrior with an Adept is a big advantage. They would lose the ability to see Spiders and improved village results, but would gain so much more. Yes, Raise Skeleton is only ONE free unit, but it is one FREE unit that can be INSTANTLY replaced for NO cost. If the Adept is sent exploring and a Skeleton is used as protection then the Adept will never be lost unless attacked by two enemies in the same turn. The Skeleton can be moved first, so that if the prospective destination is seen to be threatened by two enemies the Adept can choose to move elsewhere (the original Skeleton is then deleted, and a new one summoned, so the Adept does not forego protection by applying this maneuver). After the first two free xp, the Adept will be able to cast Dance of Blades, to make its Skeleton slightly better than a plain Warrior in combat. After some exploration the Adept could return home, and apply Blaze to give a big jump on development of Jungle tiles.
Replacing the Amurite Warrior with an Adept would be a huge advantage. Floating Eye is the best Scout in the game, and any other civ would need to research Sorcery for access to this spell (to put this in perspective, note that the Calabim will generally have Vampires before anyone has researched Sorcery...). Thanks to free xp the Adept will soon also have Haste, allowing it to move as fast as a Scout (although admittedly not on turns that it uses Floating Eye). Its base strength of 3 makes it as good as a Scout against animals (although I would send a Warrior along with it as protection, considering how valuable it is), and it can see Spiders and any other foes long before they become a threat. The vast area exposed by Floating Eye would make it very easy to find villages, so I would expect the Amurites to get a larger share of these, which would on average more than make up for the fact that the Adept doesn't receive better results from villages. Plus, much like the Sheaim, the Adept would then be able to return home and burn Jungles to unlock the potential of city sites that others would not be able to fully exploit until researching Bronze Working.
Edit: Reading MagisterCultuum's post, I realized that I had misread the proposed Amurite and Sheaim replacements as intended for the Scout, when in fact they are for the Warrior. This makes them even more powerful, because in each case it gives the civ two effective scouting units at the start.
bears will tend to hamper expeditions to the aforementioned goody huts.
