I don't think Disney itself knows. So certainly everything else is rumor.
Disney tries very, very hard to get new things up and going by June. So you can be assured they will do everything possible to have Cars Land open by June.
The rumors say that:
- Cars Land itself will likely be ready to open in June - maybe late June, maybe early
- The other significant project is Buena Vista Street - this is the new entrance to DCA. It is rumored to be trying for June but not sure if it will be July or even August
- Disney wants to open both at the same time as part of a "grand re-opening" of DCA where all the $1 billion is complete and the park is fully functioning.
- The delay in BVS might cause Disney to delay opening CL.
Here is my educated guess. And it is only a guess. If BVS is finished later than CL but not too much later, Disney will delay opening CL. But if BVS is a lot later then CL will open on its own when it is ready.
So let's say CL is complete by mid-June. As it approaches mid-June if BVS looks like it will be ready by say mid-July, CL will be delayed until mid-July so they can both open together. But if BVS looked like it would not be ready until August then Disney would open CL in June and then BVS in August.
Right now no ones knows. Not even Disney I suspect.