Beginner VSR Build Project (Input Appreciated)

Background
So I've been running a stock CYMA 701b VSR for some time now. I've finally decided to upgrade it so that it can shoot farther than 50 yards accurately. However, I am on a bit of a budget. I have the gun, a scope, and around $200-250 for upgrades. This is the list I've come up with after some extensive research, and I'd appreciate if you experienced airsoft snipers could give your opinion on my part lists. For context, I live on the east coast of the USA, and evike.com is my go-to retailer. At my local field, the fps limit is 550fps with .20g bbs for bolt-action sniper rifles.

Parts:
$99 - Angel Custom Zero Trigger (includes trigger, piston, cylinder head)
$15 - Action Army Spring (M170)
$45 - Maple Leaf Crazy Jet Inner barrel
$55 - Action Army Hopup Chamber
$10 - Maple Leaf Hop Up Bucking (60 degree)
$6.5 - Maple Leaf Concave Nub
Total Cost: $231
I'll probably be using .43 bbs

Assorted Questions:

• I was considering the Action Army Zero Trigger Kit, but it was $60 more for no apparent difference. Is there a significant difference between Angel Custom and AA? Would I be better off saving up for the Action Army Trigger?
• I'm aiming for a build that is consistent and durable. From what I've gathered, these parts are basically essential for both of those. Are there any other parts that you guys would recomend?
• I've seen several guides for choosing the correct bb weight, and I think that I will roll with .43g bbs. What would you recommend?
• I'd like to create an internally suppressed barrel, but would need a shorter inner barrel than my outer barrel. I've tried to find the cylinder:barrel ratio for my gun, but can't find the specs on the Angel Custom piston. What length inner barrel should I use with my loadout?

Main Question:
- Are all of these parts compatible with the CYMA 701b VSR and with each other? As far as I can tell, they all say that they are compatible with VSR clones and should be compatible with each other. However, I realize that using multiple brands might cause some issues with alignment. Should I get the AA trigger kit instead of the Angel Custom to avoid this problem altogether, or will it work how I have it at the moment?

TL;DR:
- Are these parts durable and accurate? What would you recommend?

Final Question:
Just one last question, thanks for making it this far. I realize that buying a lot of parts and throwing them into my gun will help, but its the finer adjustments done by hand that really make the difference, especially for a sniper. I've found assorted guides for stuff like silencing (sorbothane pads, tape, and lots of foam), tdc mods, rhops, and other things. I chose the maple leaf bucking and nub to somewhat avoid doing an rhop, and I'm pretty confident in my ability to put teflon tape and foam into my gun. Are there any other mods you would recommend? I'm mainly looking for accuracy and reliability, and anything will help. Are there any good guides you would recommend?