I can make it gradually spread over few days.
Admin access not required, only your page url.
Reference can't be provided because it's a matter of security and privacy. Every client's work is confidential when they are buying such things which is not legal in terms of service with facebook. Any such disclosure may damage client's facebook profile.
I don't live in a free world. It's fine if you wish to pay 50% later but you should be able to provide 50% before the start of work. Or another solution is to work on a per milestone basis. In the later case, I will provide you 1000 likes and on completion you can pay 1st installment and so on.