The point-to-point links would mean that the towers can see each other without any obstacle between them such as a tall building, right?
Yes.
It would also mean that the number of parabolic antennas tells how many towers the tower is communicating with.
Generally, Yes.
But, it could be that there are two antennas at different heights carrying exactly the same link.
This could be for redundancy, so that if one antenna or its feed line failed, there would be a back-up antenna,
or, more likely for diversity.
If the characteristics of the radio path are likely to change, such as a link which crosses a tidal stretch of water where the received signal strength can vary considerably due to changing path lengths for the signal reflected from the water surface, the antennas are separated by a suitable distance so that the both do not see a signal strength minimum at the same time.
What does a smaller size parabolic antenna tell us about the frequency in use and the gain?
For a given antenna gain, the longer the wavelength, the bigger the antenna.
The longer the wavelength - the lower the frequency.
So, bigger antenna - lower frequency. Smaller antenna - higher frequency.
JimB