Ot will stay always the same - always, no matter what.
Works, it does not matter which ot your pokemon has - for both, dex data and evolution count. What matters is where you evolve your pokemon, it will only count as evolution in your dex when you do it on your account.
When you want to evolve, lets say, your Kadabra and need help from someone else, ask him to not evolve the Kadabra, otherwise you wont get the evo data.