I think neither of the idioms you propose works for people.
A common word is (很)活潑, usually translated 'lively' but used mostly to describe someone's personality, with characteristics such as outgoing (外向) optimistic (樂觀), etc. If you want a chengyu-like expression, there is 活潑可愛, but it is not as widely applicable as 活潑 by itself.
An antonym tfor 活潑 would be 沉穩, soft-spoken, reserved.
If you mean someone with a lot of energy and spirit you could try 精力充沛.
Another possibility is (很)熱情; this is can indicate both enthusiasm and warmth; being friendly to others, and enthusiastic about life's opportunities. Be careful with this, though, because it sometimes means 'passionate' as in romantic matters too. 熱心 is perhaps safer, though less, um, passionate. If you want a chengyu-like expression there is 滿腔熱情.