Rhubarb I’d start with your tomatoes, they’re the only ones from your list that I’ve started so far! The rest on your list are all curcubits, I’m not planning on starting most of mine for another month or so. I’ve sown melon (also curcubit) and they have come up really quickly and quite strong, I think I’m going to have trouble keeping them from going leggy before the weather is good enough to get them into the greenhouse (mine is unheated).
I’m disappointed with my peppers & chillies 
obviously tipping over the propagator didn’t help and about half of the ones I rescued have since died. Those that are surviving are not exactly thriving. I’ve sown a second batch but they’ve not come up yet. Watching YouTube one of the allotment vloggers I follow had some lovely young chilli and pepper plantlings on her windowsill, I was very jealous! I think next year I’ll start them in January rather than Feb. I might look at ordering some plants later on this year. Pah.
Tomatoes, melons, aubergines looking good though. Going to start pricking out/potting those on today I think, and sow next batch of seed - basil, okra, perhaps some other herbs and salad greens. I’ve got a new batch of labels for my label maker, i forecast a happy afternoon of playing with plants and labels ahead!
Oh and tea plants arrived! They look to be strong plants which is good as they weren’t cheap. Weighing up potting them on indoors or in the greenhouse, not sure.