Basics: Photons and how they interact with gravitons?

No, photons do not have mass.

Yes, photons are affected by gravity. General relativity describes gravity as a warping of spacetime, with photons moving along geodesics, which are equivalent to straight lines in flat space. From a GR standpoint, this is what causes light to curve around massive objects.

Gravitons aren't part of general relativity. The graviton is hypothesized as the mediating particle for a gravitional field. If it turns out that this is correct, then gravitons would interact with photons in ways that would look the same as general relativity, and would overcome the difficulties of GR at high energies and short distances.

Firstly, the idea of photons interacting with gravitons is incorrect, strictly speaking. The reason why light curves around large objects is a consequence of general relativity. What actually happens is that space-time, the very fabric of the cosmos, is bent by gravitational fields. Therefore, whilst the light may think it's travelling in a straight line (assuming photons can think), it is actually moving around a curved path.

Photons do not have mass.

Photons are affected by gravity.

Gravitational theory has come some distance since Isaac Newton theorized that gravity is the attraction of masses. We now know that that is incorrect in general, and that gravity is actually the curvature of spacetime caused by the presence and movement of energy.

So photons, like everything else, follow the curvature produced by concentrations of energy, i.e. mass.

you have summed up properly between the basic problems of a quantum mechanical thought of gravity: a thank you to locate a quantized container on spacetime whilst the properties of spacetime count on the sphere. this is a question that hasn't been responded yet.