Zakaat on a debt that is payable after a long period of time

Q: Zaid and Ahmad are partners in a business. Zaid wishes to sell his share to his partner for R10 million. The payment terms agreed upon are that half the amount will be paid cash and the other half will be paid AFTER 48 months in 12 equal monthly installments. In other words, for the first 48 months there will be no installment paid. The question refers to the zakaat obligation during this time. Is Zaid liable to pay zakat on the R5 million owing to him during these 48 months?

Standing behind the imaam if there are no other muqtadis

Q: I started performing salaah with the imaam and because another person was just there, I stood behind the imaam expecting the other person to join the salaah as well. But that person went to perform wudhu and we completed the whole salaah in this manner.

1. Is my salaah valid?

2. Should I have moved forward to go to the right of imam when I felt the other person will be late?

3. Is moving forward during salah permissible and how much can one walk forward before the salaah becomes invalid?