Here's why PUSA won't be using the fanmade names for the starters.
Smugleaf- Sounds too much like Nuzleaf, like someone else said. Plus this name is very uncreative. It isn't based off it's lizard and snake-like features, and it only credits the leaf on it's tail. And the fact that "smug" is put in the name makes me think this Pokemon comes off to people as michevious, conniving and evil. Tsutarja is in no way michevious, conniving or evil.
I believe it's English name will consist of a species of lizard or snake, and a much less general plant than just leaf. Not some irrevelant facial expression.
Wotter- Sounds too much like the type Water. It would probably confuse a lot of people, mostly younger children, mixing up Wotter with the type.
I think it's name will consist of the word "otter", but also a "aquatic" word, much less general than just water.
Boarbeque- Sounds way too cheesy. And is this name trying to say Pokabu is edible? And if it was a name, it wouldn't be one for a first form starter, rather the third form.
Pokabu's name would be a lot more uter than a pun off barbeque. And I would also imagine a "pyro" word would be put in the mix, not a type of cooking.