Okay, I'm up and showered, though not quite awake (I managed about 5 hours of sleep last night but my body is still on Central US time).
For your option 2, those dates all work, though for October 2017, I would go with the second bank statement (10th Oct to 9th Nov), as it covers the 26th October.
Also, since you have to cover 2.5 years, and May 2017 to June 2019 is only 2 years, I would also include documents from January 2019 as well, to make sure you have the whole period accounted for, even though that means sending 7 documents in each name.
So, I would go with:
January 20171.
Joint - Council tax bill (3rd January 2017) -
Source 1(4 months)
May 20172.
Applicant - Bank Credit Interest Letter (May 2017) -
Source 22.
Sponsor - EON Gas Bill (9th May 2017) -
Source 3(5 months)
October 20173.
Applicant - NHS Breast Screening (26th October 2017) -
Source 43.
Sponsor - Bank Statement (no date but states ‘10 October to 9 November’)
- since this covers 26th October(5 months)
March 20184.
Joint - Council Tax Bill (8th March 208)
(5 months)
August 20185.
Applicant - Bank Statement (13th August 2018)
5.
Sponsor - CBT Therapy Appointment Letter (6th August 2018) -
Source 5(5 months)
January 20196.
Joint - United Utilities Water Bill (30th January 2019) -
Source 6(5 months)
June 20197.
Joint - Life Insurance Statement (20th June 2019) -
Source 7So, you have plenty of sources (you only need 3, but you have 7), you're covering all 2.5 years (Jan 2017 to June 2019), and your documents are evenly spaced (every 5 months, but 4 months for the first one)

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