The rules to me seem fairly clear cut on this, however, you'll still have a battle on your hands without help:
To take the questions in order:
1) the passport and birth certificate must be notarised. You must find a solicitor or notary public that will make copies of these documents and authenticate them in law. It costs around £70.
2) they will take into account for how long the account has been opened. In any case, continuing income is of greater importance than savings: ISAs run out while jobs last longer.
3) it's fine, provided there's space. The rule governing this is:
"Applicants applying as a fiancé(e) / proposed civil partner may not always be clear about the accommodation available to them after the marriage. However you must be satisfied that they have reasonable prospects of obtaining adequate accommodation. It is acceptable for the applicant to have arranged temporary accommodation with family or friends for the period before the marriage / civil partnership."
Basically, so long as you don't have to share a bedroom with anyone, you're OK.
4) They can't take into account educational qualifications that you don't have yet. In addition, money will be your worry.
Where the Entry Clearance Officer is concerned, public funds means:
# Income Support / Jobseeker's Allowance (JSA)
# Housing and Homelessness Assistance
# Housing Benefit and Council Tax Benefit
# Child Tax Credit
# Working Tax Credit
# Child Benefit*
# Attendance Allowance
# Severe Disablement Allowance
# Invalid Care Allowance
# Disability Living Allowance
# Disability Working Allowance
# A social fund payment
None of which include the student loan.
However, you should view it in the same way as applying for a new bank loan: you have to be able to show you can make the repayments.
On my letter to the ECO, I gave a short paragraph detailing what my income was (and payment frequency), then giving a summary of routine costs and an estimate of my single-person living costs. I then gave an approximation of my monthly disposable income, as well as explaining any exceptional costs seen on my bank statements.
Now, the mortgage lender when I was buying a house let slip that they do not approve any mortgages where the person has less than £100/month disposable income
after meeting the repayments of the mortgage. I suggest you view visas in a similar light: if after you have paid for all travel/accommodation/food you have only a paltry amount of money left over, they will deem you unable to support your fiancée whilst she's unable to work.
You should work out what your income and costs are per month, and from that work out how much is left available to you. Unfortunately the directives on immigration are very vague on what "adequate" support is.
5) This is for China, but I'm sure it's similar:
British citizen provides:
1 application form
1 notarised copy of your passport
1 notarised copy of your birth certificate OR your original birth certificate
1 P60, unless you apply at the end of the fiscal year.
6 consecutive payslips
6 months bank statements
6 months statements of any savings/bonds/ISAs you have
1 copy of your land registry deed (homeowners) or 1 original copy of your tenancy agreement (tenants)
(optional - 6 months utility bills/council tax bills)
1 letter, detailing your relationship, how and where you met, your financial status, your future plans and aspirations and what you plan to have your wife do when she's in the UK.
1 copy of all correspondence you have ever had with her, so a full printout of your MSN logs, phone bills showing SMS and telephone calls, Skype call logs, etc. My proof ran to 700 pages, double-sided.
Photographs.
What I would suggest you pair do is to have her apply for another working visa in the UK, and get a job here for not less than a year. After 3 or 4 months, apply for a variation to a fiancée's visa based on HER income. Thereafter register your partnership and convert her visa to the 2 year probationary leave to remain.
Good luck