That's pretty impossible. The uke was beta and does not have the organ to reproduce. This beta×omega pair can possibly have a child.The male alpha and male beta cannot give birth in this world.
You have to remember that every omegaverse is quite different depending on the author. In other omegaverse, both male alpha-alpha can get pregnant or just the female alpha. There is already an established cannon in this omegaverse that the paired Omega and alpha cannot be separated so it's safe to assume that males here except for the omegas cannot give birth since there is a rule fate.
I don't know if you could understand that since I can't explain it clearly.
In the second couple, i think they still can have a baby since the seme is an alpha i know they can give birth too but it has a low probability..... If that were to happen we could see their baby the uke has to top seme thou.