Steve Redgrave is much celebrated here - more so than Matthew in many ways - both are very highly thought of! Rowing would be a very British discipline to feature!
Tennis is also one that would be good because the matches are being played at Wimbledon - and Charlotte Reinagle Cooper was very much in at the beginning!
Rowing medal events 1st - 4th August
Tennis medal events 4th and 5th August
From your list I see the following as definite candidates -
July 30 : Swimming Men's 200 freestyle - Mark Spitz
August 4 : Men's Long Jump - Jesse Owens
because they are both legends and already have profiles on Geni.
Strong contenders - because they are already being researched and on the tree
Decathalon final 1500 metres is on 9th August clashes with Carl Lewis but is more Historical and very interesting
Muhammad Ali Boximg already established tree - lightheavyweight division 1960 - final for this weight 12th August. but clashes with men's marathon
Charlotte Reinagle Sterry 4th and 5th finals - so could be at the beginning of the women's singles - 28th July
Matthew Pinsent - if we can use his profile but might have to make a public duplicate - again final events are all grouped around 1st - 5th
I think we are going to have to be quite flexible!