Alright, I have used all of these Pokemon before (not always these sets, but I have still used them), and I see a few things that could be fixed, as well as what looks to be some typos.
Forretress - Alrighty, Forry is a great lead, but you have such beastliness there, why not go to town? Boot Gyro Ball and get some Spikes in there, as he has the defenses to set them up, and it is not hard to do either. Besides, you aren't out much Gyro Ball doesn't hit very hard with Forry, regardless of how slow he is. Other than that your looking good.
Alakazam - I just love Alakazam, he is one of my favorite sand sweepers. First thing I see is that you have 252 Atk EVs on him, and I'm geussing that is a typo, make it Spatk. As well as a mono-attacking set works, I have been going with a Calm Mind set recently and it allows him to punish quite a few enemies. Keep Focus Blast, but ditch Psyshock for Psychic, as Psyshock just doesn't have that oomph that Psychic gives. Replace Thunderbolt for Calm Mind, as a Neutral Psychic at +1 is gonna wreck just about anything. If you want a grass move I suggest you go with Energy Ball, but I use Shadow Ball to hit Ghosts and other Psychic types. Trust me, once you have a Calm Mind or two up, you will be nearly unsttopable, just watch out for revenge killers. Another perk to running Calm Mind over a mono-attacking set is that you can't get nailed by Suckerpunch if you predict correctly.
Terrakion - Looks dandy, only thing I have to add is that you might wanna put Rock Slide > Stone Edge due to increased accuracy and the flinch chance, since you will be most likely moving first, you might as well try and get a flinch. But if you want the extra power provided by Stone Edge then go with that instead.
Sableye or Gliscor? I have never had much success with Gliscor, but Sableye is just amazing. Definitely go with Sableye. Now geuss what, your Sableye set needs some tweaking. (See below)
Sableye - Ok, you have one of the most annoying Pokemon ever, and you haven't even used his greatest selling point. The set I have used with devastatingly trolly effects is the one you should use to:
Sableye @ Leftovers
EVs: 252 HP, 120 Def, 134 Spdef
- Night Shade/Shadow Sneak
You already know the deadliness of priority Taunt, but priority w.o.w. is just insane, as you can cripple an opponent's deadliest physical sweeper before they can even attack you, which also helps with Sableye's defense. Priority Recover allows Sableye to heal his trolly self right up before the foe can hit him, and your choice of Night Shade (Hits harder) or Shadow Sneak (Yet more priority) will help chip down the opponent's HP even more. This set is amazing, so definitely give ot a go.
Slowmonster - I have never tried any other Slowbro than my faithful physical wall, but I have heard a Calm Mind set works pretty well, thing is, Slowbro is not a special wall, he is a physical wall. Last I checked, Slowbro can't learn Recover, so you will want to replace that with Slack Off. Then, change your 252 Spdef EVs into HP EVs. Calm Mind will raise your Special Defense, so put some HP in there and you should be considerably more bulky. Only other thing I have to add is that Slowbro doesn't need to be any smarter than it is, it possesses unstoppabability.
Scizor - Never used CB Scizor before but I have seen others use it to demolish unsuspecting foe's. Don't change nothin.