Wakeel discharging zakaat from his own money

Q: At times people give me their zakaat to discharge on their behalf. Once I gave from my personal money thinking that I will take it later from an amount of zakaat kept away. When I went to replace the money, I realized that the amount was already dicharged. A few days later, I received another amount of zakaat. Will it be correct for me to replace my personal money from the second amount of zakaat although my intention was to take it from the first amount?

Linking one's bank account with someone else's account

Q: Is it permissible for me to link my bank account with my father's bank account at the same bank which contains interest but I am not withdrawing any money neither am I depositing money from his account but just linking it? My account is interest free and the money in my account is not being shared with his money but the "link" is still there.  Is this permissible?