Atm, I am going to rinse in tap water every single plant (and every single leaf) even if there will be no snails on the plans. That's what I always do with my plants. I know it will take me a long time, but I am willing to do it. I will order the plants to arrive on weekend, preferably in the morning, and I'll devote my entire day to setting up the tank (filling it with the substrate, the plants, and water). Filter and heaters will already be in place when the plants arrive. If I won't have to rinse Eco-Complete, then I'll put it in the tank the day the plants arrive. If, however, I'll have to rinse it, I'll do it a day or two before I receive the plants. And when the plants arrive, the gravel will already be in the tank, in this case.
Omorrokh ... hmm. If Rose wasn't the only one, there is a good chance I may get the snails as well

Hmm, maybe I won't order from AquariumPlants.com after all ...

Thanks a lot for the info.