Please, help me with my questions !!!

Hello!

Please, help me with the following:

1) "Ms.Kate, a friend of her mother's...." (what is the meaning of her mother's here. Shouldn't it be "a friend of her mother or her mother's friend" ?);

2) What's the meaning of 'ever since' ? E.g.: Ever since he was in the army, he has studied hard;

3) "He lives at 341 Bourboun street apartment 23" (in addresses must the word street be translated from a foreign language into English ? E.g.: In Spain street is 'calle'. In this case when I have to say my address in English do I translate the word 'calle' or not ? E.g.:

4) I live at 201 Cervantes calle apartment 101 (or) I live at 201 Cervantes street apartment 101 ? ;

5) What do we call a organized group of soccer fans that goes to a stadium to watch a soccer/football match ? Is it called organized claque or organized supporters ?

6) People who stay outside a stadium trying to sell tickets at a higher price than at a ticket office, are they called street peddler of tickets ?

7) A special service in which the employees' service is to listen (by phone) to citizens general complaints, for instance, about the bad services offered at a stadium, is it called Ombusdman office ?

Thanks,

Muriel