If you want to be as budget conscious as possible:

1) Use your current hammock if you already find it comfortable. Maybe add a ridgeline, play with it to get it how you want

2) A bugnet can be found on Amazon for as little as $20

4) While on Amazon, you can also get a tarp for $30-$40. Sometimes the cheap ones can leak in heavy rain, but a can of this would help with that ($9)

3) For insulation, I have a set of these off Etsy. Lowest I have used them in was low 50s but I slept well. Their post says 40F but I'm dubious on that. Currently they're $160 for the set but I got mine cheaper. Granted that was years ago, so I couldn't tell you if they were on sale or just raised prices since then unfortunately

That would get you sub $250. You can also mix/match any of the above since you have a decent budget

I would prioritize insulation first. Sleeping warm in a cheap hammock will be better than cold in a fancy one. I haven't used any of the HG stuff, but they are highly rated and I've never seen anyone on here have any complaints about them