For many people here both of you guys have "Wish list" , but the time line you gave and the ships you described are Much needed and this is all do able.
1500 tone ship is more likely FAC or very fast and small in seize covert , we can add that too.
The main thing is "Availability" and war planning , If we want our Navy strong and want to give them any chance against Indian Navy we need bigger and Better ships. It will take time and money but because of time it is doable .
People need to understand we don't have to pay 10 or 11 Billion $$$ in one year , this payment will be divided on 10 or may be more years , As
@MastanKhan described it very well in 8 sub purchase .
With CPEC and new energy plants our economy will improve so we can give some extra to Navy each year , and don't forget my suggestion "Public Fund" for Navy where every one can pay his/her donations.