I believe all those parts should make it through.
The high-flow valve goes in the magazine, and releases gas when the hammer hits it. You'll need a valve key to replace the magazine valve. Empty the magazine, then use the valve key to unscrew it, then simply screw in the new high-flow valve. Make sure you put a drop of lightweight silicone oil on the o-rings.
A modified screwdriver may also work instead of a valve key.
Propane is good for regular use. Just get an AI propane adapter kit as it includes the lightweight silicone oil you need to add to the propane tank intermittently. You can also use this to lubricate o-rings and other rubber parts.
For lubing the pistol, make sure all the metal-on-metal contact areas are lubed. You can use a heavier weight silicone oil or white grease that doesn't have petroleum distillates (they harm rubber). Available at Canadian tire
As for an AEG, you should decide on what model you want first. Based on that we can recommend brands.
There are many 'obscure' guns. Basically anything that is not an M4/M16/MP5/AK is pretty much an obscure gun. Masada/SCAR/AUG/F2000/G36/G3 are just some examples. So read up and do some research into which style appeals to you.
H&K G36c (KWA) / Glock 18c (TM) / Kimber LAPD SWAT Custom (TM) / Mossberg M500 (ACM)