Oh wonderful!
I'm glad to see you came back and added some Pokemon to your team! However, we still need to know whether or not this is a UU team, or an OU team. I mean, right now, all of your Pokemon are UU.. which again, as I have stated before, is just fine as long as you're not trying to play in a standard environment. So just let us know exactly what this team is supposed to be, because there are other Pokemon in OU who outclass some of the Pokemon you currently have.
This seems like a pretty good set. There's really nothing that's any worse or better than what I'm about to recommend. Gallade has access to Psycho Cut- his primary Psychic type STAB attack. So, I suggest: Close Combat / Psycho Cut / Night Slash / Stone Edge or Ice Punch with a Life Orb. This set is pretty much like yours, but it allows Gallade to attack harder with the Life Orb support, but that's not to say that there's anything wrong with Shadow Sneak. Now, I would recommend a Choice Scarf/Band, but the main reason why some people don't like a Choice equipped Gallade is because there are just better users of Choice items out there. It really just comes down to personal preference, it might work for you and make Gallade less reliant on a priority move, it might be a severe hindrance. Anyway, Close Combat and Psycho Cut make up most of Gallade's offensive integrity, while Night Slash takes care of the Psychic types that resist them. Stone Edge is just a strong attack and Ice Punch is for coverage, but they can also be substituted with Shadow Sneak, X-Scissor, Earthquake, Brick Break, Leaf Blade, Focus Punch... and a bunch more. Also, Gallade uses Status effecting moves pretty well, with access to Will-o-Wisp, Thunderwave, and Hypnosis.
As far as EVs are concerned, it is safe to say that Gallade is in a different class in terms of Speed, so it may not be *necessary* to invest EVs in.. but in this Metagame, Gallade needs all the Speed it can get, in my opinion. With 252 in Speed, Gallade will be able to outspeed an Adamant Tyranitar at it's lowest, and a Jolly Weavile (with Scarf support) at its height. With a Jolly nature, full EV investment and Scarf support.. Gallade will be outseeding the likes of Crobat, Aerodactyl, and Jolteon. That being said, Gallade could also make good use of some EVs in Special Defense as it's typing doesn't resist special attacks very well.
Gallade is a Pokemon that I suggest you test out for a bit. Find out what you think you'll need the most between all power, all speed, status effects, Choice items, or a defensive variant.
Porygon-Z has an exceptional Special Attack, obviously. So a Choice Scarf is an exceptional item to complement that. However, Nasty Plot is totally viable in tandem with a Life Orb. However, with your current set, I recommend dropping Trick Room. It will not work in your favor when you're Choice-locked and slower than your opponent (maybe you just meant Trick?) Thunderbolt is an excellent option and Ice Beam (for the ever classic, BoltBeam) can walk on eggshells around everything that resists Tri Attack. Also, give some thought to Hidden Power [Fighting], which can take out Magnezone who resists Tri Attack and BoltBeam. Overall, you're not far from a very good set here. Well done.
Now, I'd like to address a problem with your team as a whole. You have a pretty staggering weakness to Fighting, as only Gallade resists it. Everything else takes neutral or super effective damage (more of the latter). So, adding a Pokemon that resists Fighting or does super effective damage back will help balance this. This will depend on which tier you want to play in. So, let the raters know and then we can start recommending good teamates for your Pokemon!
I hope this was helpful!