Security issue concern

"prevent from copy-out/check out but at the same time allow client cache to be populate with an auto delete upon closing the document"

This makes zero sense. Prevent from copy-out/check out means they can't open the file at all so you don't have to worry about the second part. You can prevent copy & check out by denying them access to the file altogether.

"allow client cache to be populate with an auto delete upon closing the document" is not possible. In Projectwise you can have it delete the file (and references) on check in or free but not on close (you would be risking all the work they did if you could). 

"Or hash the document in the local cache so it can be read only by an authorize client. The decrypt key will be set randomly in the admin panel and change every X minutes."

This is not a feature of ProjectWise. You could turn on full disk encryption in your Windows but the user will always be able to read the file. Generally speaking full disk encryption is protection agains the hard drive/laptop being stolen, not protecting users of the machine from copying files. FDE is also a bit of a protection against people booting up a different OS on a USB stick or CD drive and reading the disk from the alternate OS.

blocking print screen doesn't stop people with a phone with a camera on it, which is almost everybody. you also have to block printing because they can just print and walk out with the document. If they actually need to print then this isn't possible.

The captive environment setting only works with software that is actually integrated with Projectwise. So Bentley software, most of Office 365 (but not all), some Autodesk, InDesign from Adobe (not even sure it works on that integration). And I'm not sure it's 100% coverage. For example the Backup command on MicroStation can cause a copy of the file be made into an arbitrary location. It doesn't even switch to the other file like a Save As... does. VBA can probably do something similar bypassing even that key-in.

BTW, Something similar has been discussed before. I know Bentley had a DRM product at one time that might help but only with PDF files. It added DRM to the files so that even if the file were copied access could be blocked. I think this is no longer available?

https://communities.bentley.com/products/projectwise/content_management/f/content-management-forum/80090/secure-document-proposal

Thank's again Kevin DRM sound like something interesting, will keep that on my watch list