hmm...my $0.02
1. The ex-CNS said the vision is for 20+ large surface combatants.
I think he's referring to ships of 2,000+ tonnage, so that would include 4 F-22P, 4 MILGEM, 4 Type 054A/P, and 2 OPV 1800s. That is already 14 ships. He said the PN is going to contract another 6 ships of 'larger tonnage' down the line.
2. The Jinnah-Class Frigate is a standalone project.
The J-Class is not tied to the first 4 MILGEMs, but a separate program that is still in the design phase. However, since it is a frigate, it would be part of the 20-ship vision.
It's quite possible that the PN is basically planning to acquire 6-7 J-Class Frigates, and the J-Class will be a 'larger tonnage' design. Basically, it could end up being a 5,000-6,000-ton frigate like the FREMM.
Of course, since the PN likes blowing expectations out of water, I'm probably wrong.