Are you going to try a hardfork?
I think is better option to launch a new coin/algo and let us test it out by mining first. Then when we see there's no "difficulty" problem we can swap coins from the old unify to the new one, manually or maybe using the service novaexchange offers
https://novaexchange.com/coinswap/.
So, it would be like this.
1- Launch a new unify coin/algo
2- Premine the already unify circulation supply to future swap
3- Mine the coin for a couple of days and test theres no difficulty problem.
4- If everything works ok. Swap the coins to the new CHAIN.
This is just a suggestion if you prefer a hardfork its ok.