Alakazam would do pretty well for your team, however it isn't a "Bulky Offensive" Poke.
A potential moveset could be:
Alakazam @ Life Orb
Magic Guard
Modest/Timid
6 HP, 252 SpAtk, 252 Spe
-Psychic/Psyshock
-Focus Blast
-Shadow Ball
-Substitute/Anything Else
This set allows you to have lots of coverage, against Dark Types, Rock, Ghost, etc
Also, you could sacrifice one of the moves for Dazzling Gleam if you'd rather the coverage against Dragons & The Like
Also, I wouldn't waste my Mega Stone on Alakazam. While it does make him more viable, he is good enough without it & there are perhaps some better uses to having a different Poke with a Mega Stone. Other choices could include Mega Mawhile, Mega Lucario, Etc would be good options (Unless you choose to use Aegislash). I don't know how viable Mega Ampharos is in OU, but she could be an interesting option
Edit: Mega Ampharos probably isn't a good option, didn't realize her Speed stat was so low. Would definitely do work on a Trick Room team. However, she can certainly be defined as a "Bulky Offensive" Poke
Edit 2: I just though of a possible set for her,despite how bad she may be w/o Trick Room. Since I'm new at this, someone please critique me & let me know if Mega Ampharos is even viable w/ & w/o Trick Room. Nevertheless:
Ampharos @ Ampharosite
Static/(Mold Breaker)
Modest/I Don't Know
252 HP, 252 SpAtk, 6 Spe
-Dragon Pulse
-Thunderbolt/Thunder
-Focus Blast/Signal Beam (Maybe?)
-Volt Switch
This Set would be a good definition of "Bulky Offensive" as Mega Ampharos can dish out damage & certainly be capable of taking a few non-resisted attacks. Dragon Pulse & Thunderbolt/Thunder are there for stab. Focus Blast is there for some coverage (Perhaps Signal Beam is also viable for Psychics? Idk....) and Volt Switch is there just incase it is necessary to Switch Out because of a Fairy Type,etc. Even though, now that I realize it, her terrible speed probably makes her a very bad Volt Switcher. Oh well, perhaps you could use something else to replace that.