Hailey's ring has a halo of diamonds embedded below (it's like a pave band but for the setting itself), it's also in yellow gold. I inserted the picture. The only thing same between Leonie's and hers is the stone shape, but nothing else.
Tamara I believe has white gold or some kind of white metal and Leonie (or her boyfriend) fully copied this style of engagement ring (setting, metal etc)
I dont think oval rings are anything special personally, I dont like the way Leonies ring was set because it has strong flawed shadows which are shown and visible even from the picture.