I'm certain Forest Mist is a cue, but I've just seen Jim Ware below me say that it is. As for the UE Gungan's March... that's just an insert with reverb over where the real March begins. It's a separate cue, but I still have no idea where it goes. It is heard cleanly, without the single horn blasts (A Ben Burtt addition, I'm sure) on Track 14, whcih brings us to...
The UE 'Gungans March' is 'Drums Insert' and replaces most of the tail-end of 'Forest Mist' (you can hear the very end of 'Forest Mist' after 'Drums Insert' finishes).
Considering the Droid Invasion follows The Armies Face Off, followed by Tentacles, High Council Meeting Alternate, Darth Sidious and then the opening moments of DOTF, I wouldn't put too much stock in the OST's order. As I said I believe this is an insert piece. As to where it is to be inserted, I do not know. One theory of mine is that it preceeds Forest Mist and goes straight after War Plans, so we see the Gungans marching to battle before Sidious receives the news of the army, then Forest Mist kicks in with the Trade Federation Army responding. This theory also says that this is the Forest Mist piece, but I'm absolutely unsure of it.
The OST does at least put part of 'The Armies Face Off' in the correct place - immediately after 'Drums Insert'. The rest of the cue isn't on the OST, but can be heard (edited) on the UE as 'The Queen and Group Sneak Back Into the Palace'.