Published software not displayed in Add/Remove Programs

The GPResult output shows that the target computer account (i.e. the COMPUTERNAME$ Active Directory account for the machine you're using) doesn't have permission to the software deployment GPO you created.

The target account(s) (i.e. computer accounts, in your case) need both Read and Apply Group Policy permissions, in the Security settings for the GPO you've created. (At the bottom of the Security tab in the Group Policy Management console)

Note also that if the installation isn't silent (i.e. displays UI) and you've not created a silent installation MST for it, it'll hang the computer when it boots (while waiting for invisible user input), for 15/30 minutes.

Note that as of MS16-072, you need computer accounts to be able to read (only Read, not apply) group policy in order to be able to apply User policy. https://blogs.technet.microsoft.com/askds/2016/06/22/deploying-group-policy-security-update-ms16-072-kb3163622/

Have you tried forcing the policy on the OU? You may have another policy that is blocking the application of the policy. I'm assuming that the XADistribution policy is the one containing your package? Once done you can force replication (assuming more than one domain controller) and then force a group policy update with the gpupdate /force command. You can then re-run gpresult to see if the policy is being applied. With that in place I believe a reboot would be necessary to initiate the package installation.

Group Polices have security permissions. There is permission for "apply group policy" that you have to check for users/groups that you want the Group Policy to apply to. You get to the security settings throe the property button on the Group Policy tab.

To publish a software put it under the "user"-tree.

To force a software to be installed put it under "computer"-tree.

May you choose the wrong path when you are clicking the GPO together.