family visitor visa docs n funds

[khimani.amir]

hi,
Thnx to this forum for always giving guidance on immigration..i have been using this forum since i was on tier 1 general and now i m still using it after receiving my british citizenship..Many thnx to all the admin members..
I got my british passport in june 2014 and i want to sponsor my sister(who is a divorcee), who lives with my parents in india and unemployed..following are my concerns:
1) my sister doesnt have her surname in her passport..will there be any problem with the visa?
2)i m attaching the following docs..plz let me know if thats enough:
a)myself and my wife's passport copy
b)6 months bank statements(mine and my wife's)
c) 6 months payslips(of myself and my wife's)
d) sponsor letter
e) tenancy agreement
f) no objection letter from landlord
g) employers letters( mine and my wife's..we both are part timers)
h) savings account of my sister(60000rupees)
i) divorce certificate

3) how much funds do i need to show? my account has been in negative last month..will that be any problem for visa?
4) do i need to maintain the funds for 3 months or so? or only the final balance is important?
5) my parents have fix deposits of 5000£ each..do i need to add their statements as well?

thnx in advance