well, u already answered yourself!
Is the Pirc a good choice for a Sicilian/KID player

Pirc is employed in top level when one is in a must win situation.
It's a perfectly fine opening but employing it because it looks like KID is a wrong reason that will most likely lead to changing the opening a few months later , once you realise that these 2 openings have only superficial similarities.
Hmm.. intersting. I think one of the sub variations of the Pirc is like the KID. If white goes for a Yugoslav attack kind of setup then i think it is like the sicilian.

Indeed, Pirc and KID are really different.
Playing KID, i tried Pirc (also because it was fashion amongst friends), and I stopped 3 months later...
For example if u compare Saemisch on KID and f3 variation on Pirc, the fact c2 moved or not creates a huge difference...
Anyway, the best way to get an opinion is testing it yourself.
For a dynamic opening, the french is a pertinent choice to me.

French is good but you have to work very hard with the opening .. i mean during the actual game. Most of the time you are trying to achieve a marginal advantage.

The Pirc reminds me of the Alekhine in some respects: it's possible to get really interesting, double-edged positions with chances for both sides, but White has to play ball. If White isn't ambitious, then you get an 'equal' position but where it can be hard to do anything.
When I tried the Pirc, I got a lot of classical set-ups (Nf3, Be2, Be3, 0-0) and lots of e4, d4, c3 pawn structures, where White was content to have a small, stable plus. I found these variations dull (I'm not playing a hypermodern opening to get positions like this!) and stopped playing it.
By contrast, the Modern (1...g6) was a lot of fun. It's almost always possible to transpose back into a Pirc, or at least a KID, but there are also other options. If White plays classically like above, then there are ideas of e6 or e5, Ne7 and then f5, reaching a double-edged position; the Knight can also go to h6 instead to support f5. Finally, I could leave my King in the center and play funny things like h5, h4 advances. All of these ideas made the games more fun and dynamic, at least when White was content to play unambitiously.
I eventually stopped playing the Modern because, chiefly, I could never play the KID to save my life, and too many people started going 1.e4 2.d4 and 3.c4. If I ever learn the KID I'll certainly pick it up again.

I would add that one problem with the Pirc is that there is no clear plan (contrary to french for example), and u have to adapt to the many set up white can play.

I'm looking for a very sharp and dynamic response to 1.e4. I find that opening with the Sicilian offers too many choices to white who can play along closed lines should he choose to. However, with the Pirc I feel like I can get Sicilian type positions unless white simply relinquishes his advantage by squandering it on meaningless moves. I also like the KID. So should Pirc be the right choice if this is the case. I dont really fear the Austrian attack and few people know it anyway.
I was a pirc player but you need a lot of theory knowdelage to play it properly

The problem with everything you do in chess is predicting the future.
Today Pirc is fine , will it be fine tomorrow? That's the critical question.
The point with Pirc is that the pawn structure can remain undefined for many moves while in French things are clear after the first moves , you know what you need to do and how you need to do it. Black's dilemma has to do with the type of play he wants. In Pirc it's either e5 or c5(in some cases even d5) but things become even more unclear as White can exchange advance or support and each one of those has more choices that lead to even more pawn structures and you have to be very well prepared for all of them. Add to that the choice to delay any central action in favor of a flank attack which allow some early e5 breaks from white and you have an opening that is the definition of "chaotic".
The practical problem with that in low levels is that the player improves without the opening improving with him and that eventually becomes an issue once he has to deal with stronger opponents. It is quite common D-class players to be forced to change their openings once they are B-class, not because they are not good , but because there is a geometric progression of the practical difficulties as the opponents become stronger and stronger.
Totally agree with that. And the reason why the Pirc is so good is because it is chaotic.
I'm looking for a very sharp and dynamic response to 1.e4. I find that opening with the Sicilian offers too many choices to white who can play along closed lines should he choose to. However, with the Pirc I feel like I can get Sicilian type positions unless white simply relinquishes his advantage by squandering it on meaningless moves. I also like the KID. So should Pirc be the right choice if this is the case. I dont really fear the Austrian attack and few people know it anyway.