It's a good question, and one that I'm still working on answering. I have part of the answer though.
Thanks for providing a picture, it helps!
First of all, Yes, I agree that all 3 of those cards you pictured are from the same set.
There is no doubt with the Scryb Sprites & Llanowar Elves.
The War Mammoth is more difficult to identify. Italian Second Edition & Italian 4th Edition both have a 1995 copyright, so some cards are harder to tell apart. I've checked though, and the Italian 4th Edition War Mammoth uses a much smaller font in the text box. Your War Mammoth is Italian Second Edition, just like your Scryb Sprites & Llanowar Elves.
I am interested in your War Mammoth. (I might even ask to purchase it in the future.) Can you tell me where it came from? Do you know if it was opened in a booster pack or starter deck for example? Having this info would be helpful towards solving the mystery.
Yes, some Italian Second Edition cards have a bolder copyright line, while other cards do not.
I hadn't noticed the Power/Toughness difference before, but from other cards I can look at, this and the copyright line both seem to be unrelated to the mana symbol difference that you've pointed out.
In addition to the mana symbol difference that you pointed out, there is also a slightly different font used for the card name. You won't be able to see it on your card because only some of the letters are different. i & j
The mana symbol and card name font changes do go together.
Italian Second Edition had more than one print run. On the first print run, some of the green cards had dark colored text boxes which made the lettering difficult to read.
These cards had the dark text box issue fixed for the second print run, and the card name font & mana symbols were updated on the fixed cards.
Your War Mammoth is a fixed version from the second print run.
I think the Scryb Sprites & Llanowar Elves did not need fixed, so both print runs look the same and yours could be from either run.
The copyright line & power toughness doesn't appear to have changed between print runs, it's the same on both, so that's a different issue.
Here's some pics.
1st print run on the left, 2nd print run in the middle, 4th Edition on the right.
