The design looks very good. I have some questions.
1. As far as I remember, you've got the gain of slightly worse than 10 for a 55MHz single resonant case. Why your expectation of the gain (G=11) for the highest resonance better than this?
Supposing the loss exists only on the EOM, the other part of the LC network for the triple work as an inductor at the resonant frequency. This is just equivalent as the single resonant case. So the expected gain at 55MHz should coincides with what we already have. Probably, the resistance of 4 Ohm that is used here had too rough precision???
2. How can you adjust the resonances precisely?
Do we need any variable components for Cs and Ls, that may have worse quality than the fixed one, generally speaking.
I myself has no experience that I had to tune the commercial EOM because of a drift or whatever. I hope if you can adjust the resonance with a fixed component it should be fine.
3. Changing Cp. What does it mean?
Do you put additional cap for Cp?
4. The resonances for the lower two look very narrow. Is that fine?
This will show up in a better shape if we look at the transfer function for the gain. Is this right?
If we have BW>100kHz, it is sufficient.
5. Impedance matching for the lower two resonances.
Yep. You know this problem already.