Intel HD 2000 Performance estimation on this scenario?

With so many variables, the answer clearly is "benchmark it". It's impossible to give even a ballpark figure in this scenario.

To elaborate on the totally correct answer above:
Something like "database calculations" could mean anything from a dozen requests that take thousand CPU cycles each (which is nothing) to thousands of request per second, of which maybe 4 or 5 will blocks in disk I/O (which is something like 2-3 frames at your desiered frame rate).

Similar can be said about "pathfinding" and "physics" which may have a complexity 4 or 5 orders of magnitude different based on some "minor implementation details". Physics simulations can run at upwards of 100fps on a single CPU core, and physics simulations can take 2-3 minutes for one frame on a dedicated GPU. IK can be immensely complex, or very simple (basically free, in some cases), depending on the implementation.

2000 agents that do not much except follow a target and shoot it (maybe in a group) are different from 2000 agents that are scared, get hungry, seek for cover, and call for help.

"Using shadows" can mean at least 4 entirely different things (fake ground shadows, projected shadows, shadow volumes, shadow maps) and roughly 50 variations of the latter two with a gigantic span from one end to the other.

The question as such just can't be answered, given the details.

Intel HD 2000 is a GPU and most of those items are only relevant to the CPU.

Can a mobile quad core CPU for Intel HD 2000 keep up with a minimal frame rate of 25 in this case?

Yes... if all those things that you've listed take less than 40ms to compute You'll have to add timers to your code to keep track of how long each part takes per frame, and then optimize them until they do take under 40ms.

As for the quad-core part -- do you use 4 threads?