Your remittances are in normal banking channel. My recommendation is to remit money directly in foreign currency, then convert it to rupees at local bank and get encashment certificate from bank. And remain non-filer.
In case FBR asks about your assets in future, just show encashment certificates and they won't bother you no more. You don't even have to tell them source of remittances if you receive less than $100,000 per year.
These payment processors are bad for remittance tax exemption. I receive dollars through Payoneer, they convert it to rupees and then transfer it to my bank account as local interbank transfer, all the proof I have is their email of currency conversion rate which is not acceptable proof of remittance encashment. Same as you the company I am working with don't send wire payments to Pakistan.
About PSEB registration, its complicated procedure, you also have to be registered with State Bank and report monthly export figures with details about contracts. I was registered with PSEB since 2007, but then few years back they made it mandatory to register with State Bank and submit monthly reports otherwise PSEB registration won't be renewed, which is yearly renewal for 10,000-30,000 Rs depending on revenue. It was getting too complicated as a single self-employed person, so I stopped renewing PSEB registration and now submit tax return as "Foreign Income" since I receive low remittances these days resulting in little tax.
Best option is remittance encashment!
