Prithvi 1 , or what mostly remains in service with the Army were either fully modified to a P2 version or received an guidance upgrade. In Army role P1 with only the upgraded guidance systems is operational with a view to use it as smart munitions carrier actually. In case of a conventional conflict the aim is to fire these P1 from close to border with engagement ranges being as close as 50km to as far as 180km. A battery firing a few dozen missiles will do the job of hundreds of guided Excalibur shells.
How many and in what configuration they remain exactly is something which I don't know. But their replacement will depend on how the Rocket Force is shaped.
The SFC specifically received the Prithvi 2 (ssm250) if i am not mistaken. P2 often dubbed as IAF variant, we should remember when the SFC was first created it was IAF chief heading it. 250km to 350km with around 280-350kg of nuclear warhead with pretty good precision is what is currently held. Weight is sometimes said to be as low as 180kg, but that's hopefully we will never know.
Coming back to SFC assets. Prithvi 3 is an available capability, not a deployed asset as of now. In late 2010s when talks started, it was conveyed by the forces that inducting a new liquid fueled short range system was not worth it. Agni 1 was by then operationally deployed.
As and when Agni 1 is out of service, we will then need a new platform in SFC for that SRBM role. The Agni 2 units have been either upgraded or replaced with new Agni 2 improved missiles. I don't know exactly. But they are operationally deployed. Numbers unknown to me.
When Pralay comes in, the requirements with respect to Pakistan will be fulfilled. Agni 2 now can carry nuclear warhead upto 3000km. So range will not be a problem for SFC with respect to Pak imo.