Ok, as I most likely have the highest skill set in most areas ... here goes. The answer, after trying about everything, is I think NO. You can not get prospero through any means when your at some distance.

First, you can not trigger a portal to open on a CCC andmore than on someone protected.

Second, almost all the skills I think SHOULD work on summoning Prospero wont. The main problem lies in our inability to ORDER PROSPERO LOYAL CASIMIAN. If we could do that, then we should be able to use several music skills . like PLAY HORN PROSPERO, or PLAY PIPES PROSPERO to get him. Another skill that depends on the CCC being loyal is CALLING in Survival, shich also doenst work for the same reasons.

If anyone finds a way to do it, let me know :-) ... It would certainly be an interesting ability!