Yes, they have the same meaning. And yes, "point" refers to a particular moment in time. You can also say "from this point on" with the same meaning. A couple corrections... 1. No "s" is needed in "forward" or "onward." 2. In the second example, it is talking about a time in the past because of the past tense used ("was completely won over"), so you should say "From that point onward..." Any of these sentences would be correct: From this point forward, this is our outpost. From this point onward, this is our outpost. From this point on, this is our outpost. From that point onward, the teacher was completely won over. From that point forward, the teacher was completely won over. From that point on, the teacher was completely won over.

Yes.

Note that both of these expressions are rather rare and unnatural, though correct. From now on, this is our outpost. From that point on, this was our outpost. After that, the teacher was completely won over. Also “this point forward” can be used spatially. So if you are talking about time, “onward” is a little clearer.