Firstly, I think you’re nuts! Catering for that amount of people when you’re not used to it is crazy. But it’s lovely that you want to do it for your daughter.
I would look into hiring a fairly simple hot-plate set up to keep food warm - that would alleviate your worry re serving food at the right temperature.
I think you want everyone to feel that they’ve eaten well, not just shoved a few sausage rolls down their throats.
If it’s a “standing” event, the most important thing is making it easy for the guests to eat their food. Look into hiring small/individual-sized simple white bowls. These can easily be held in one hand, makes it easy to eat whilst mingling.
Then look at, say, three fairly simple dishes that can be batch-cooked and kept warm on said hot plate set-up mentioned above. Thoughts off the top of my head are:
Some type of vegetarian risotto (there are cheat ways of doing risotto so you don’t need to be constantly on it stirring all the time).
A slow-cooked beef/veg/potato type stew (thick rather than runny gravy/sauce)
Thai red/green curry - could be chicken/veggie etc
For desserts, I’d be cheating and getting a load of individual servings from a supermarket, they all do fairly decent stuff.
An alternative, to take ALL the pressure off you, is to hire a catering service that provide a flying buffet service. Yes, it costs, but it saves you buying/cooking the food etc. plus they clean up the mess at the end of the night!