IIRC, it was the 41 yo white Lt. Rice bike cop who initiated the pursuit of FG, calling for backup along the way, and the two young, white bike cops responded. If so, there was only a "he" after FG and no "they" until later on. I definitely think Nero and Miller, who on video seem to be handling FG with care, were over-charged.
I don't think the charges stem from the take down and arrest (except for the false imprisonment). Each of the officers were present at other stops along the way to the jailhouse. If you read the statement given by Mosby, she details what actions were taken at the stops that corresponds with the charges. For example Nero and Miller---
False Imprisonment -Lt. Rice, Officer Miller and Officer Nero failed to establish probable cause for Mr. Gray’s arrest as no crime had been committed by Mr. Gray. Accordingly Lt. Rice Officer MIller and Office Nero illegally arrested Mr. Gray. Upon arrival of the transport wagon driven by Officer Caesar Goodson. Lt. Rice Officer Miller and Officer Nero loaded Mr. Gray into the wagon and at no point was he secured by a seatbelt while in the wagon contrary to a BPD general order. Lt. Rice then directed the BPD wagon to stop at Baker Street.
(Possibly assault? by placing him back in the van unsecured) At Baker Street, Lt. Rice, Officer Nero and Officer Miller removed Mr. Gray from the wagon, placed flexi-cuffs on his wrists, placed leg shackles on his ankles and completed required paperwork.
Officer Miller, Officer Nero and Lt. Rice then loaded Mr. Gray back into the wagon, placing him on his stomach, head first onto the floor of the wagon. Once again Mr. Gray was not secured by a seatbelt in the wagon contrary to a BPD general order.
THEN, there was the second stop with the video from the market that we have not seen yet. (I don't think.) We do not know who was present.
Later, (failure to get him medical attention) --Officer Goodson arrived at North Avenue to transport the individual arrested at the location of North Avenue and Pennsylvania Avenue at which time he was again met by Officer Nero, Miller and Porter. Once the wagon arrived, Officer Goodson walked to the back of the wagon and again opened the doors to the wagon to make observations of Mr. Gray.
Sgt. Alicia White, Officer Porter and Officer Goodson observed Mr. Gray unresponsive on the floor of the wagon. Sgt. White who is responsible for investigating two citizen complaints pertaining to Mr. Gray’s illegal arrest spoke to the back of Mr. Gray’s head. When he did not respond, she did nothing further despite the fact that she was advised that he needed a medic. She made no effort to look or assess or determine his condition.
Despite Mr. Gray’s seriously deteriorating medical condition, no medical assistance was rendered or summoned for Mr. Gray at that time by any officer.
http://time.com/3843870/marilyn-mosby-transcript-freddie-gray/