Im pretty sure it will be Simultaneous. If its like most other TBS games (well honestly, I only have MP experience with BTS), then there will be a slight lag, and a combination of a faster computer, faster internet connection, and "fast moves" will decide who is to grab the goody hut first.
Also, at least on the strategic map, mobile units will have a great advantage. Luckily for us, we fight in TACTICAL battles, so you can't simply fast-move a victory "thank god".
I remember moving a giant army of horsearchers onto City C. Before they even knew what was going on, City C was taken and destroyed (I *might* have captured it). See, they were in the build screen for City C, trying to decide what to build next. The Civ 4 interface was *awful* by the way, espcially for the degree of complexity that FFH required, or at least suggested, that you include in your combat strategies.
So in these cases, it was always best to have a giant stack that did one thing. Like Spectre Spamming Mages/Vampires, or Fireball Spamming Firebows/Golems, Or HorseArchers that moved hella-fast.
In addition, when you lose a city you are currently "INSIDE" your game crashes. So when I took his city that he was still making changes with, he crashed and we *would* of rehosted, but he was already pretty much dead. That was his capital IIRC.
That game was known as another "Hippus Raze the World" game. Somehow the Doviello Player and Lanun player really check-mated each other, so by the time I got to them, I didn't actually die. In fact, it would have been alot worse for me if the Lanun army was actually in their cities. See, they were off fighting the Doviello and I razed their cities .....
Anyways, CIV 4 interface, horrible for FFH2. You almost always had to save build-ques for the end of your turn, (minimize popups) and alot of the time you had to turn off unit cycling just so that you could select your whole army before the UI selected some lame soldier half the map away. Also, with later patches the Ctrl+# function stopped working for groups of units, so you couldn't even "KEEP" a coherent army, you had to reselect them every time.
The only winning factor was that clicking "alt" would select all units. Although it was SOMEONE's brilliant Idea to have Alt favor naval and aerial units. So if you had ONE HAWK it would just select the hawk, instead of your 10 hunters, 20 axemen, and 5 catapults. .... same goes for Coastal Cities with ONE GALLEY.
Spammable magic was an almost sure fire winner. Mainly because Fireballs and Spectres = free units per turn. There is really nothing other than a pre-built army that can compete with that. Spammable magic means that you can build a unit from scratch and it will have a spell. Fire Golems, Vampires, Arcane Barges, Firebows all had this.