Diggle and Lyla having a son, John Jr., instead of their daughter Sara is an after-effect of Barry Allen creating the Flashpoint timeline in "Flashpoint (2016)".
When the gang blow up the bank, they place a bomb on the outside of the wall, which would blow the wall inwards, but the wall blows outwards towards the bomb.
Although Vigilante's primary weapon is the MP5K in 9mm, the rifle with grenade launcher he uses at the hotel is chambered in 5.56mm. When the team is at the gun store earlier in the episode they ask about 5.56 armor piercing hollow point ammo. Armor piercing ammo does not have a hollow point as that defeats the purpose. A hollow point expands quickly dumping its energy into a target and does not penetrate much. A hollow point on hard armor would just disintegrate. Standard 5.56 mm, like the majority of rifle calibers, will penetrate most soft armor.
The team attempts to find information about Vigilante by questioning the owner of a gun store. All three members ask the owner about 5.56 mm hollow point ammunition, however Vigilante carries an H&K MP5K which is chambered in 9 mm.