Yes, the similarities are to be expected as the two engines were ordered and built side by side at a single manufacturer. Apparently from what I've read at that time they were naming locomotives after animals so it was to be expected I suppose.
Mind you that sort of tradition carried on throughout pretty much the entire steam era in the UK, well at least until British (Boring) Rail came along and just numbered all the new locomotives. Examples of this are;
A1/A3 locomotives (aka Flying Scotsman type) were typically named after race horses
A4 locomotives (aka Mallard) were generally named after birds, so you had 'Seagull' etc... Just a small number were named either after famous individuals (eg. Sir NIgel Gresley - the designer) or various commonwealth locations such as Union of South Africa and Dominion of Canada.
Southern Region 'Schools' class were named after famous British schools/colleges such as 'Eton' etc...
Southern Region 'Battle of Britain' class after various RAF squadrons, airfields or famous Pilots/Commanders.
Southern Region 'West Country' class (which look almost identical to the BoB class) after famous towns in the west country such as Exeter or Bodmin
Southern Region 'Merchant Navy' class were named after shipping lines such as 'Clan Line', 'United States Lines' etc...
Princess Class - Named after Royalty typically
Coronation Class Named after UK Cities
The list goes on and on...
But an interesting subject for sure