I think the best bet for both Pervez & Monis and PTI would be that the duo should keep their own party and register with the EC as PMLQ Parliamentarian on the lines of PPP and PPP Parliamentarian.
After registration with the EC, like Sheik Rashid's qalam dawaat PML become ittehadi with PTI.
Having one's own party in politics have many fold benefits.
BUT if it becomes inevitable then welcome them in PTI on certain terms and conditions. Then keep Pervez in Punjab and Monis in Center.