My thanks to KGarrad and Crisane for their thoughts on the age Victorians married. One thing discovered in this time-detective hobby is not to make assumptions but to examine every possibility.
The name of the game here is to find out the maiden name of the Ada who married George Colebrooke in 1896 and the only way to do that is to check the marriage certificate. Someone has already found out this information as they stated that Duriah Lovell (Ada Lovell's father) was named on that marriage certificate:
http://www.gypsyjib.com/search/everything/george%20colebrooke?contains=george%20colebrookeHowever they didn't mention the father of George Colebrooke, so if anyone out there has that certificate do let me know as this will prove which of the several George Colebrooke's mentioned in Ancestry is the correct one. The George Colebrooke mentioned on the 1911 Census is perhaps, the same one who married Ada Lovell but we won't know for certain until Ada's maiden name is confirmed.
The troubling part of all this is the sheer volume of consistent family stories which connect Ada "N" to north American First Nations Tribes and how Ada "N" described herself as related to either Sioux, Pawnee, or Cheyenne tribes (all depending on who's telling the story).
There can be a lot of value in family lore as you know. Speaking from a personal example, my father told me his mother received 7 telegrams from the Mercantile Marine relating to her brother who's ships were targeted by German U-Boats during WW1. Naysayers discounted this story for many years until recently a distant cousin found the information in WW1 records at Kew and Newfoundland and proved that my dad's uncle was on board a number of ill-fated ships and unfortunately lost his life on the 7th ship when it was attacked in the Ionian Sea in 1918. I digress but hope this example shows the importance of family stories...
I know that in the case of Ada "N" naysayers galore are asserting that there is no American First Nation connection whatsoever but I am hoping that someone somewhere has the information proving or disproving the link definitively.