ILR and Universal Credit

Hi every one...
Few questions
1 Time period.....
My wife enter in UK on spouse visa in December 2015.
Her 5 years will be complete in UK on December 2020.
Can she apply for ILR in December 2020?
2. Universal Credit....
Only I am working full time and meet all the financial criteria
Earn around 20000 per year. But I am claiming universal Credit as well .
Will it effect my wife ILR application ?
3. Documents.......
Do I need to submit 5 years documents with ILR application? For example 5 years bank statements

Help me with these questions please

Thanks

1. Yes
2. It has no effect on her application
3. You need to meet the financial requirement and also submit two years of cohabitation documents