Of these, the general forms pêe and nóng are used as personal pronouns and are also used as titles before someone's name, though the way they are used is somewhat different.
pêe is by far the more common, and is used with people who are (very roughly) up to 15-20 years older than you. It's considered to be a term that shows respect, and so people will often use it even if they're not sure if the person they're talking to is really older than them or not.
When speaking to, or referring to, older males, both men and women commonly use pêe as a title. So for instance, a man called ต้น ( dtôn , usually written as "Ton") would often be called พี่ต้น ( pêe dtôn , which would usually written as "P' Ton") by younger friends, junior office colleagues, a (younger) girlfriend or wife etc. If the context made clear who was being talked about, this could be shortened to just pêe . Similarly, he may choose to refer to himself as pêe instead of using a standard personal pronoun. The same rules apply when talking or referring to older women too, although it's a bit less common.
nóng can be used in a similar way, although it should be used somewhat with caution. As pêe implies respect, the opposite nóng could potentially imply inexperience or lack of status, and so be a condescending form of address to someone who views themselves of equal status. Because of this, it tends to be used when there's a very clear age difference (5+ years) or when the relationship between the parties is clearly defined, which ensures there's little danger of a misunderstanding. If used correctly, it's viewed as a friendly and polite form of address and not uncommonly used a boss and his/her younger employees, or a older man to a younger girlfriend/wife. One of its other most common other uses is when calling to an obviously younger waiter/waitress in a restaurant.