MOSFETs don't work with AC, and they don't isolate the high-voltage from the low-voltage, which you need for safety.
Make sure you get an AC
solid state relay. The input/control side of a solid state relay will usually work from 5VDC. But unlike most mechanical relays, the output/load side of a solid state relay is usually designed for either AC or DC.
The light doesn't draw more than 5A but I would like to play it safe and use components that can handle up to a 10A load anywhere the 'high' voltage lines are involved.
That's always a good idea
. Plus, most AC loads have a higher "inrush current" when 1st switched-on.
I recently finished a project where I made 4 solid-state relay circuits and built them into a 4-gang (8-outlet) electrical outlet box. I did it because I could make the circuitry smaller than a high-power AC relay, and it was cheaper. But, my 1st design has some mechanical-construction issues, so it took 2 attempts to get it right.
It's possible to make your own solid-state AC relay from a TRIAC, a special triac-driver optical isolator, and a couple of resistors. But it's (relatively) high voltage & high current stuff, so you can end-up blowing parts (or electrocuting yourself) when you are building, testing, and troubleshooting. Plus, it's a time-wasting distraction that can delay completion of your project.
I recently completed a project where I built 4 solid-state AC relay circuits and installed them in a 4-gang (8-outlet) AC outlet box. I did it because I could make the circuitry smaller than regualar high-power AC relays, and it was cheaper. I've made a similar circuit before, but I had some mechanical-construction issues (I broke the leads off of some optoisolators), so I had to order more parts and re-design & re-build it before I got it right.