Short answer is yes, you can take VSS snapshots on volumes with CHAP enabled if you are using NWT (Nimble Windows Toolkit) 184.108.40.206 or above. There is one exception though - one specific configuration of Exchange - if you are taking Exchange snapshots with the verify snapshots option on then CHAP cannot be enabled on those volumes. Otherwise you are good.
Regarding timeline of supporting Exchange with verification option turned on with CHAP, can you please contact your local sales team? I cannot share future capabilities on a public forum.