[Citrix UPM - Google Chrome Exclusion]

Yes, can be excluded but first try to disable "Prediction" in Google Chrome, see this: https://admx.help/?Category=Chrome&Policy=Google.Policies.Chrome::NetworkPredictionOptions

[Black screen after selecting VDI]

You should use latest version of CVAD. According to CTX224843 only 2206 or newer (for CB) or 2203 LTSR CU1 or newer (for LTSR) is supported.

[Stop Error 0x0000005D appears when Installing Windows Server 2012 on XenServer 5.6]

Performance and experience will be better if you can install XenTools though.

[Stop Error 0x0000005D appears when Installing Windows Server 2012 on XenServer 5.6]

This applies to XenServer 6.x - i don't think that Server 2012 runs on XenServer 5.6.x