Probably been done before, but I was bored:
The old Baroque Works agents were never featured in the time-skip cover pages because Crocodile actually re-recruited them all (Minus Bon Clay and 3) and Oda's saving their designs for when he comes back into the main story. They've all been put through a hard grind to catch-up to the power packs of the New World.
Mr. 5 has bulked up and trained hard to become more of a close-combat fighter. More of a wrestler/boxer type that wants to get in close and explode where people can't dodge him as easily.
Observation Haki Usage to help him read opponents and make landing devastatingly explosive hits easier.
Miss Valentine has similarly trained for more close-combat fighting, with more of a martial arts focus. She uses her devil fruit much more freely now to throw people off as her speed makes constant, instant changes based on her weight level.
Armament Haki Usage for some increased durability and to coat her already heavy-hitting limbs for maximum damage.
Mr. 4 has doubled his speed and increased his strength to the point of wielding a 10-Ton Bat now.
Armament Haki Usage typically on his bat before striking actual people.
Lassoo no longer has a cold and freely blasts baseballs without sneezing. Now also can shoot alternate baseballs from his backside. His backside shoots flammable gas bombs to increase the devastation of his normal bombs.
No Haki, but possibly Awakened Zoan for increased durability.
Miss Merry Christmas has become an Awakened Zoan. Much more durable and strong enough that just about anything is the same as digging through sand was for her back in Alabasta.
Observation Haki to more easily track people above ground.
New Mr. 3 is just a generic strong man guy that's constantly under Miss Goldenweek's hypnotism. He mostly carries Goldenweek's stuff around and is her bodyguard. Not actually important and nobody cares about him.
Miss Goldenweek's hypnotism is now essentially one of the strongest in the series at this point, which Crocodile makes great use of. Along with the stronger hypnotism, she now has paint guns, paint bombs, and a paint bazooka to better defend herself (alongside New Mr. 3). Goldenweek is basically Crocodile's partner now as the other executive (Robin's old position), but refuses to take the Miss All-Sunday name, preferring Goldenweek.
New Mr. 2 is actually Gangster Gastino. Kinda a longshot, but he just disappeared partway through WCI, not even appearing with Bege's crew towards the end. If he did actually leave his crew, I'd love to see more of the guy and Crocodile's crew is probably the best place for a mobster like Gastino. Probably wouldn't get much respect though.
Miss Doublefinger beyond normal strength/power upgrades, has added heavy knowledge of acupuncture to her arsenal. She focuses on targeting specific points in her opponent's to disable and incapacitate them faster and easier than a full fight. She also will dope her own allies if they need a boost in power at a given point or need help healing certain injuries.
Mastery of Observation Haki which she uses to hone in on points in her opponent's bodies more easily. Also able to use Armament Haki to harden her spikes against more dangerous opponents. Possibly Awakened Fruit as well.
Mr. 1 mainly mastered some Haki and drastically increased his personal strength and durability to catch up with the normal haki-users of the new world that could all cut him.
Mastery of Armament Haki to make his body and blades strong enough to class with the top ring of swordsmen around. Also uses Observation Haki for basic uses. Likely Awakened Fruit User as well, able to turn things around him into blades as sharp as his.
Crocodile himself will be our first full explanation of what an Awakened Logia can do. Likely doesn't need to touch things with his hand to dry them out anymore, just his normal sand can do it, and he can probably turn full biomes into desert without much time or effort. To be fair, we'll actually see Crocodile and Mr. 1's upgrades eventually, so I didn't spend much time on them.