You can give away what you don't have and there are no grounds in law for this to be contested - EXCEPT possibly by Suzie, but no-one knows she is his baby so no-one will bring the claim.......
Re giving away what you don't have "I leave all my worldly possessions to x", tomorrow I get given a house, the house is included in 'worldly possessions', thus it goes to x.
If the will says "I leave my share of the factory to Aliyah" then, again, it goes to her.
If he says "I leave x number of shares in the factory to Alyiah" then she gets x number of shares and the rest fall to residue (which is the bit where you say "and everything else to....y"). If 'residue' has not been bequeathed anywhere then that section will fall to intestacy rules.
If any falls to intestacy, then it all goes to Johnny (is there a mother, I can't recall) though it would go to Suzie if anyone knew......
And, if it does all go to Aliah (no idea how to spell her name, sorry) Suzie could contest as she could claim she has a 'reasonable expectation of financial support' - though this would be pretty difficult to prove as her mother has given her away and had no intention of telling Aiden of her existence, and she will be supported by her new family.
I think Michelle will tear up the will, pretend she never saw it, and it will all go to Johnny and then Eva will make the claim on behalf of Suzie (and take her back) which Johnny will be happy to allow, and then Eva will leave with the baby (who will come back in x years and wreak havoc, of course).
Mind you, soaps are not known for bothering with actual law :)