Splashing Marina as a 4 star card is petty dumb, since she and welee both need their bonuses to be effective nukers.
The only cards which are viable for splashing (elo) are:
Spaghai, Cyb Lhia, Spyke Nabrissa, Cwing, Parmabarb, Pegh (when using alongside spaghai) and almost any Skeelz card that isnt support, lehane.
There may be a few others, but I wouldnt stray too far.
Wee Lee will not make a splash card. Nor will Marina. They've been around for years and years and yet I have still never seen a deck with either splashed in. Wee Lee will be a powerhouse, a 4* 9/6 with a decent dr ability is good. Picture him as a mini Tanaereva Cr.
Ulu Watu will not be strong in ELO again for a long time. Like bangers, they just don't have the essential cards that all other clans have. This happens everytime a new card is unbanned - players want to experiment the first few weeks. Ulu Watu will not stay in ELO long, and Wee Lee only strengthens them. But alike Lehane release, people will stop using the clan purely on 1 card. You just have to give it time.