Yes, PTI without Punjab govt will be a mostly toothless govt and I really hope that doesn't happen. Pakistan really needs PTI to govern and reform Punjab like it was done by PTI in K-P for the last 5 years. Also, the Noon League can be very effective opposition in Punjab and groom its new leadership for 2023. In the end, who knows, Imran Khan may not be able to 'deliver' and people may wish for Shahbaz Sharif back in 2023. Noon League must see political wisdom in becoming an opposition in Punjab Assembly.
Having said that, I think the Independents would go the way of the party ruling the Center and so it's almost certain PTI will form the govt in Punjab.
PS. PTI should not let Zardari off the hook by getting his 6 MPA's support: PPP's corruption and mismanagement of Sindh in last 10 years is a crime of epic proportions and so even if it takes making a Forward Block in Punjab to not appease Zardari then so be it! I hate Forward Blocks but some times they are better than the alternatives.
PTI is looking to strengthen institutions by making them independent. I don't think it will be up to them who NAB and other agencies prosecute. This is the way forward. No to political influence in FIA/NAB/FBR/MI/Police