Convert Minecraft Microsoft, question?

I now know that all Mojang accounts will be converted to Microsoft.

My question: Can I use a Microsoft account even though the Microsoft account is used for the Poket Edition?

That's fine.

I do not recommend that you change anything yourself, as the Mojang migration has not even started. Otherwise it can happen to you that nothing works, because all your data / skin is still with Mojang and not with Microsoft.