UK Spouse/ Fiance visa requirement

[vanescy]

Hi everyone,

Here's my situation: I'm from Hong Kong and have been worked for a company with the YMS visa which it will expire in the coming August 2017. My boyfriend is a British Citizen and he is currently studying in Uni. We are planned to get married before my YMS visa ends and apply for spouse/ fiance visa. We just have some questions about the financial requirement and documents to submit.

I currently earn £17,510 per annum which does not meet the minimum financial requirement, my boyfriend has £11,000 savings in his account since January 2017 but it does not meet the savings requirement as well. For this his parents are willing to transfer him some money so that he will have around £20,000 by the end of March 2017. When combing my income and his savings we should have just passed the minimum financial requirement:

Savings: (£20,000 -£16,000)/ 2.5 = £1,600
Combined with my income: £17,510 + £1,600 = £19,110

So here's the questions:
1. My boyfriend's savings is not hold at least 6 months in his account, will it be the reason that the immigration will reject the application?

2. What documents that we need to provide to make the application more success? We have been together since 2014 and have live together since that year as well, so that we are able to provide bills or letters to prove we are living together for at least 2 years.

3. If we open a joining account now, will it be helpful to the application?

4. If we can get the visa and by the time we have to renew it after 2.5 years, can I use my income only to meet the financial requirement? (Assumed my income at the time for renewal is over £18,600) Because I'm pretty sure the savings £20,000 will not be maintained by the time for renewal.

Many thanks for the patient to read this and your help in advance.