Raichu-Seems fine. Consider a hidden power to cover a bit more. If you're gonna use this for a specific tier on PO besides Mixed, then I would consider a different pokemon if you aren't going NU.
Floatzel-I would Highly suggest using a standard physical set in this case. Though a special set is unexpected, that doesn't make it a good idea. Floatzel has paper thin defenses; he won't have time to set up a rain dance. Focus blast and Blizzard are also unreliable, even with the wide lens. According to a few of my stat calcs, his physical moves will be stronger using weaker moves than the higher base power with his lower special attack. Tyranitar will rip him in half before he can set up that weather. Also, you should fix up his EVs; every bit counts. You can still fit in 4 evs, rather than the 255.
Calm mind sudowoodo. Is it creative and unexpected? Yes. Is it practical? Not so much.
Charizard-His set is fine, but if this is for PO, and not for mixed tiers, then you should probably pick something besides him, as stealth rock is very common. If you still want to use him, then having something with rapid spin would be a great idea. As with Floatzel, he's missing a couple of EVs. A different item would also do him a bit of good, as his current one is fairly situational.
Serperior-I'd suggest giving him some kind of hidden power. Ground is a good one to break through heatran; rock can be used to cover 4 of his weaknesses; fire can be used to break through steel pokemon that can wall him out, as well as other grass types. Rather than a miracle seed, you could use leftovers to give him even more health. If you're gonna go with mirror coat, then I would suggest using reflect, so your opponent is more inclined to use special moves.
Tyranitar-This one is fine. A life orb might be a bit stronger, but he's tanking enough as is, so This one will be fine.
Lucario-You have plenty of special sweepers as is. I'd suggest going a bit more physical if you're gonna keep Lucario here. Life orb would be a nice choice on him if you're gonna go for sweeping.