I don't think Magik is going to be in the MCU. if she was, it won't be the Magik you know from the comics. Magik been a child is a problem for the MCU to get her right correclty.
Anyone who has read some comics, knows Dr strange and magik will make a good duo, but so far both characters are going to end up in different corners. if new mutants succeed, Magik is off completely. Don't expect X-23 to show up either.
lastly, we don't need any mutant characters to be a black widow candidate. that to me is overplaying the crossover angle.
MCU should just do the right thing and introduce mutants in the traditional way, this is X-Men. trying to tie them up to other marvel characters is not what makes xmen interesting, in theory it is the opposite that made them interesting. x-men is mostly secluded. let the movies show it that way, it will also give more believability to why mutants are hated and feared and other marvel heroes are not and that is if mcu is going to make mutants hated and feared, because I am doubting they would. there is too much complicated themes and drama in that aspect of hated/feared and complicated themes and drama have never been the MCU strongest strength.