alright i respect that
firstly, how often do you get punctures? I don't think a tubeless conversion is necessary. Simply a new tyre, even one that is not super puncture-resistant, should mean you practically never get punctures. I would not worry about replacing your wheels.
Secondly, before you replace your chain, buy a chain wear tool. Measure your chain wear. If it's not .75, don't replace it. If it's .75, replace it. If it's 1.0 replace it, and replace the cassette.
for pedals, if you want something -good-, i would recommend FOOKER.
for chain, i would recommend KMC. 7 speed and 8 speed chains are the same btw. So you can buy an '8 spd' chain. KMC is nice because the quick link means you can easily take the chain on and off reliably if you want to change things on the bike, whereas a shimano chain which you connect with pins, is reliable, once, and then if you remove it with a chain tool (you can) it might snap when you reconnect.
for forks, i would recommend you find something locally and used and otherwise don't fucking bother and that one comes down to you and what you can get and yeah. Work out if it's 1" or 1 1/8" and threadless or threaded before you look. And make sure the steerer is long enough. Geometary is a thing but probably not necessery to worry about. Your best bet might even be buying a donor bike and then you could get a nicer crank too.