1. The original buyers' (as per sale agreement) address is in India but they are actually NRIs, if that is the case what is the necessity for them to sign the MOU at a foreign country and get it attested by the Embassy or a notary public of that country, then the purpose of showing local address will be defeated.
2. The POA agent is not going to execute the registered sale deed in your favor, he will perform the task of signing the assignment deed, which is an unregistered document, hence there is no necessity for the POA deed to be adjudicated.
3. Let one person authorise the other person to receive the amount on behalf of him/her by issuing an authorisation letter duly attested by a notary public of that country and the person who receives the amount should acknowledge the receipt of entire money which forms part of the co-seller too.
4. It depends on what else your advocate would suggest after rendering legal opinion in this regard.
5. The advocate who gives legal opinion would be the better person to oversee this and point out any technical flaws in this.