My next question is, regarding the financial requirement, will it be the same salary or savings minimum for my partner?
Yes, it's the same financial requirement.
Once you have the FLR(M) visa you will be allowed to work, which means that you canc ombine your incomes to meet the financial requirement for the second FLR(M) visa (after 2.5 years) and ILR (5 years).
And are there any additional documents they will request that were not part of the finace visa (apart from marriage certificate)?
It's mostly the same, but for relationship evidence, instead of showing communication between you, you need to provide evidence of living together in the UK.
So, you'll want to get your names on bills and things ASAP and also make sure you get sent paper bills in the mail. DO NOT go paperless on anything.
You'll need 6 documents addressed to both of you at the same address (either jointly or separately), evenly spread over the time you've lived together (up to 2 years)... although if you've only just moved to the UK, you may not have 6 documents, in which case, you submit what you do have and explain why you don't have 6 each yet.