My understanding would be:

• Probabilities: Chance of a certain outcome happening. E.g. Outcome A has a 70% chance B a 20% and C 10%

• Possibilities: what outcome scenarios exist. E.g. there exist 3 (A B C). Those Possibilities might have a probability associated with them

• Plausibility: looks at the degree of truth of a statement. So if it logically makes sense and is the correct answer/is what happened. You might make a judgement of the plausibility of a possibility based on the probability of it happening. Say if something has two outcomes one with a 99% chance and the other 1% then that might be the more plausible one. Or if it has no chance, then it might be implausible

Edit: since someone mentioned the example of a coin toss.

Head and tails have a probability of 50% each (for the sake of simplicity I assume it won't land standing up)

A coin toss has two possible outcomes (possibilities). Head and tails.

Someone says he flipped a coin and got head 1000 times in a row. That's not plausible with a fair coin because of the low chance of it actually happening (even if there is a indefinitely small chance). As a result you might assume he is either lying or the coin is weighted for that outcome.

1. Probabilities - The mathematically determined chance that something will happen given a specific scenario.

2. Possibilities - The set off all things with a >0% chance of happening given a specific scenario.

3. Plausibility - The outcomes of a specific scenario, that when presented to a reasonable person, that person would determine that they are possible.

Coin toss:

1. Heads or tails are 50/50 probability.
2. It is possible that the coin lands on its side.
3. It is implausible that it splits in two.

1. Decent chance of happening.
2. Is theoretically possible but unlikely.
3. Could happen, but there's no data on how likely it is.

Probabilities will likely happen.
Possibilities could happen if chances go right.
Plausibilities could, within reason, happen, but are not necessarily likely.

Possibility: it can technically happen

Probability: statistically significant likelihood of happening

Plausibility: a possibility that passes the laugh test

Probability is a numeric value between: 0 and 1 of how likely an event is going to happen. Depending on the definition, I would say that possibilities and plausabilities are both events with a nonzero probability. Colloquially, possibilities are more likely than plausabilities I guess. Source: two thirds of a stats phd and C2 level english skills lol