Glad to be of help with the chart and acompanying details.
Hopefully I will get up to London either this coming W/E or 19 May. I will certainly get you a copy of Edwins marriage, Arthurs marriage, GF's marraige and his birth (I'm sure I must have the reference).
The death certificate for Edwin will give the address at which he died, his occupation, cause of death,the witness and witness's address. The Will/Letter of Administration is lodged at a different office. It may not give any more information than 'everything left to widow Sarah' on the other hand it may detail each descendant and the property left to them. I wasn't actually planning to go to the office where the Wills are held. Which is more useful is debatable - if the witness is a relative other than his widow then it could prove the link, and the occupation is a good pointer on the other hand he could have been in a hospital and the witness be the doctor! Either way its a gamble as you can't view before you buy. Personally, I like to knowtheir cause of death (there are haemophiliac Fray's in London).
Margarets death certificate I think needs to be obtained - if she didn't die and there's no divorce he couldn't have married again. I wouldn't bother with certificates for Alice, if Margarets cause of death includes complications resulting from child birth I think the evidence is conclusive enough.
I could get the actual print outs for each census reference at the same place as I order the certificates. It is time consuming winding each reel to the right place then queueing at another machine to get a print which is why I don't ususally bother but the charge for print is minimal (less than 50p a print) so I'll do them if I get time. If not you should be able to order the reels from your LDS centre.
If you agree I'll buy them on a credit card and then let you know the total. I'm not sure of the 'cheapest' way to send money - You may want to enquire if the bank has a 'minimum' charge.