Asking About Modifier

Hi all, i'm new to the forum. Nice to meet you!

I would like to know which part of these sentences does their modifiers modify.

(1) The dog of the fire station, which is very big, jump out of a car

(2) The dog of the fire station at the end of town that is very big, is running

(3) The cake in the kitchen is eaten by John that is nice

(4) Visitors to the park have often looked up into the leafy canopy and seen monkeys sleeping on the branches, with arms and legs hanging like socks on a clothesline. <<<<< [[[[modify Visitors or monkeys or could be both?]]]]

(5) What made the moment right was the return of African American soldiers from the First World War in 1918, which created an ideal constituency for someone with Garvey's message of unity, pride, and improved conditions for African American communities <<<<<<<[[[[modify "What" or "the return" or "African American Soldiers" or "1918" or "could be anything?]]]]

Secondly, I would like to know which part is the modifier of this sentence and which of the sentence does the modifier modify

(6) In these difficult economic times, those who have public pensions – veterans, mail workers, firemen, and others – are being pursued strongly by pension advance companies, which operate without much oversight from banking regulators but are now drawing scrutiny from several other government organizations.