QSFP+ ports on EX4300 switches are configured as VCPs by default.
"All 40-Gigabit QSFP+ optical ports on an EX4300 switch are configured as VCPs by default", which you are able to observe as vcp in your output.
see the kb fyr.
You may use, request virtual-chassis vc-port delete pic-slot 1 port 0
to convert vcp into et ports.
You may use show virtual-chassis vc-port to view currently available vcp interfaces on EX series.