The 1917 renumbering of the TF is covered on http://www.longlongtrail.co.uk/soldiers/a-soldiers-life-1914-1918/renumbering-of-the-territorial-force-in-1917/renumbering-the-tf-infantry-in-1917/
240452 was given to someone very early on in the sequence for the Leicester's 5th TF Battalion. It would be highly unusual if his renumbering just happened to conicide with a move of battalions, so we can take it that 2219 was his previous number in Leicester's 5th TF Battalion.
In theory, once you know the number sequence, you can get a rough idea of when someone joined. FMP has a Thomas Birch number 2247, in the 1/5th and 2/5th Bns - these are just subdivisions (battalions in their own right) of the 5th. He enlisted August 1914 so William Smith (at 2219) probably enlisted about then. Roughly. So that's a volunteer, he wasn't conscripted.
So Medal Index Card William was a Territorial, not a reservist, which is a concept only applicable to Regulars - Territorials were a sort of reserve by definition so would never be referred to as reservists.
It's most likely that the 1911 WES is someone entirely different. Without seeing the stuff, I would take a guess
that 1911 WES is a regular, as any territorial should give their daytime occupation in a census. That being so it is very unlikely
that 1911 WES would end up in the Territorial Force as former regulars who wished to carry on in a part-time capacity, were encouraged to join what was referred to as the Special Reserve.
Please note that all the above is full of estimates and educated guess work intended to give you some idea of the likely things to investigate first.