Okay, so you need 6 documents in each name, 1 per person every 4 months from Feb/March 2016 onwards (and if they are separately addressed they should be from the same month, preferably dated within a few days of each other).
From your list, you have 12 applicant documents and 13 sponsor documents. However, 3 each of those are printed from online and may not be considered, so that gives 9 applicant documents and 10 sponsor documents.
For the required 4-month spacing, not counting the online printed council tax, you have:
Feb/March 2016
1. Joint: February-2016: Water bill
June/July 2016
2. Sponsor: July-2016: Bank statement (sponsor).
2. Applicant: July 2016: ?
Oct/Nov 2016:
3. Sponsor: ?
3. Applicant: ?
Feb/March 2017:
4. February-2017: Water bill (joint).
June/July 2017
5. Sponsor: June-2017: HMRC tax code letter
5. Applicant: ?
Nov/Dec 2017:
6. November-2017: Nursery invoice for payment (joint).
Additional extra:
Feb/March 2018
7. February-2017: Water bill (joint).
So, for the correct spacing of months, I count:
7 sponsor documents
4 applicant documents
However, since you have 9/10 documents each (not counting the online ones), hopefully they will consider those, even though they aren't the correct spacing of months and aren't dated in the same month as each other.