having ClearCase and ClearQuest license, can I have RTC licenses?

If you have a CQ license (with paid up maintenance), you are entitled to a special RTC license that is functionally equivalent to a Contributor license (i.e. lets you perform work item and planning operations).   There is no corresponding entitlement for a Developer license if you have a CC license, but there used to be a special license you could purchase, that was only slightly more expensive than a CC license, that let you use both CC and RTC (I don't know if that special license is still available for purchase).