Regarding William Webb. The only definitive information you have is that he was a soldier when he married in 1873, and his father was named Thomas.
You cannot be sure which army regiment (or regiments) he was with at any specific time; I have not found any military records for him.
You don’t know when or where he was born; you don’t know when or where he died. Also, he has unfortunately, a very common name.
The information given by his 2 sons when they married, about their father, is conflicting, and may not be accurate.
If you want to progress further, you would now look at the 1877 birth certificate for George Henry WEBB, as any information provided about the father William and his occupation may give you better direction.
I do suspect George was being fanciful when he says his father was a "tailor" – but maybe there was some grain of truth?
From the records, George Webb appears to have quite an extensive military career, and he must have joined the army when still a teenager.
• 1st battalion Queens Own Cameron Highlanders 1641 Sudan, Africa (1896-1899) & then transferred to 1st battalion Welsh Regiment, Cairo
• 2nd battalion Seaforth Highlanders 4693 Boer War (1899-1902)
• WW1 - Royal Inniskilling Fusiliers D5797594 Lieut / A Cpt
Eli Webb, before joining up again in 1914 with the Highland Light Infantry, had at some time spent 4 yrs with LRV, and 4 yrs with the Cameronians (7th Scottish Rifles).
Eli’s and George’s time in the military is worthy of note. For George it explains why he doesn’t appear in the England / Scotland census in 1901. The fact that neither are findable in the 1881 census (as young boys) is curious. Possible explanations would be that the family was either abroad with their father on military exploits, or had returned to Ireland with their mother.