As cheeky as this might sound, I'm serious: for the challenge. Let's say the Estonian team wins against one of the other teams, they will be celebrated, while if the other team wins, no one will see in it an achievement. While the Estonians don't even have to win at all, any goal would likely be celebrated. And maybe it's not even about the competition - I'm sure the Estonians would be happy about the opportunity of such a match.
But, I'm totally fine with it, that you want to have balance. But I see several possibilities (but will stick to call the race Estonians, because I don't know which race is currently in need of some boost). Give the Estonians a bonus on some weapon, which the others can use as well, but the Estonians have a bonus on it (fits to all races I guess; orcs might have clubs, dwarves definitely axes or hammers, etc…). And to give the Estonians now a special boost (without having to do much programming etc) just introduce extra strong Estonian-favoured weapons. No one would profit of it as much as the Estonians, and you can give an easy and quick, but still lore-friendly boost. The same way just downgrade the weapons (or in general equipment) which favours a currently overpowered race. Maybe you could also make individually adjustments to the max levels. Maybe the race gets older or dies younger - would explain, why they have a higher/lower max mortal level. Or it takes more/less experience to gain a mortal level.
I think to fully understand what you try to achieve, but imo the chosen/favoured solution is neither the easiest/quickest to implement one, nor does it stand out for any specific reason as possibly best (I don't see what could be achieved by it, which can't be achieved by any of the other options). I even think replacing stat differences by skill differences is not necessarily a real solution, because it is likely that you just replace the cause (now stats) of the imbalance with a different cause (then skills). You could just simply adjust the current differences (makes less work than introducing new skills and you at least would benefit of the experiences gained so far and it would be more of a re-adjusting), but new skills sound exciting, so there is nothing wrong with new skills. But it's neither necessary to introduce race-skills, nor to remove race based stats, in order to achieve balance. Another approach could also be, if the stats are currently favouring races, just with the new skills to favour the other races (I think if balance is necessary at all, then only in total - it's fine if a race might suck by skills but rule by stats).
Don't get me wrong, this is no "Stop! How dare you?" I am far too little and haven't seen anything here, maybe already next week I myself can't wait for things to change. I just think the approach HOW it shall be solved seems to likely to replace issues with new ones for the cost of what would make sense, butd also what new players would expect during character creation: that a dwarf is stronger than an elf, and an elf smarter than a dwarf. If you don't tell the player then, they will be likely disappointed as soon as they find out. Now you could tell them during creation "stats are not (or maybe not much) different", then most players will be surprised (and probably not positive surprised, but for sure surprised). You can tell them then "but you will have different skills", which only leads to more questions and they just wanted to create a character and jump into the game. There isn't so much anyway, what one could call "common knowledge" in the fantasy genre, but those few should be really sticked to. I'm not much into fantasy but was surprised that the blacksmith in Dwarfheim is closed; it seems as likely as a Nintendo console without any Super Mario titles. If I would find an axe, which can't be wielded by dwarves I probably would report a bug, because even I know that dwarves are small, drink, etc, and are masters with axes and in blacksmithing, but suck in magic. And those expectations are intended, or you wouldn't have chosen to use use races people mostly know, so I really wouldn't break with those expectations now either.
I think differences (especially, but not limited only to stats) based on race are an important part of the whole fantasy thing and are expected, but they are also a great opportunity to not have to think about balanced skills either (favour the skills of those with a disadvantage in stats, and give those who are currently favoured with stats* the crappier skills). And when you notice the next imbalance, you will have two additional options for adjustments (you can lower the skills/ boost the stats of the one, or increase the skills/ reduce the stats of the other).
*but ignore the spell casting of humans since it is based on a bug. And do the same for all other bug based issues. Those bugs will be fixed eventually, hopefully soon.
But those are really just my 2 cents. I feel like im not worthy to object, since I'm too new. I'm therefore absolutely fine with it if you go to fully ignore my view. Just wanted to share this view