1. What kinds (if any) of missions will come with ACE?

It remains to be seen. ShackTac/BAS have created a special version of the BAS Mission Framework that is specific to ACE, so aspiring mission designers will have a lot of help in that area. I can't speak as to what the beta's mission selection will be, though.

2. What kinds of infantry and vehicle classes will there be? ie: Rifleman, Automatic Rifleman, Automatic Rifleman Assistant, GPMG Gunner, GPMG Gunner Assistant, etc.

Pretty much everything. There are far too many to list. There are many new vehicles and tons of infantry variations.

3. Will there be any special considerations needed to transform missions to be "ACE Compatible"?

You will probably want to rebalance all missions to cater towards ACE. You can play them without doing so, but it may not provide the best gameplay. ACE introduces a very different pace and difficulty level compared to normal ArmA, and you get the best results from designing your missions to account for this.

4. Will the new "ArmA Island" feature predominantly enterable buildings? (might as well try to ask it hehe)

Nothing further to add on this one for now.

5. Any attempt at adding thermal imaging for various vehicles? Smokescreen launchers/generators? AA countermeasures?

Thermal - yes, we have a thermal-esque script in development. It's not going to be a groundbreaking thermal imaging system, but it will get the basic idea across. ArmA does not really allow for proper thermal without an absurd amount of work, at least from what we've been able to tell so far. Smokescreens/smoke launchers, yes, they're on appropriate vehicles. AA countermeasures are in as well.

6. What kinds and types of markers will be included? NATO, Warsaw Pact, Others?

NATO at the very least.

7. Any plans for artillery (mortars, howitzers, missle/rocket)?

Yes. The end goal is to have CoC's Unified Artillery for ArmA as the artillery backend. In the shorter term, we've acquired a new team member who has created a very similar system that should serve us well in the interim.

8. What kinds of man-portable heavy weapons are included? HMGs? TOWs/missle systems? Mortars?

Mortars will be in a future release. HMGs, grenade machineguns, and TOW/AT crew-served weapons are all either implemented or in the process of being implemented.

9. Plans for claymores or other types of mines? Tripflares? Hand launched (no weapon needed) paraflares?

Claymores, mines, etc - yes. Tripflares, I believe so. Hand-launched flares, I'm not sure, but they could be added in the future if there's a desire for them.

10. Any plans for IR weapon sights to be used with NVGs?

Not currently. It may be possible and may be worth pursuing in the future, but at the moment it's not on the list.

11. Any plans for flashlights for weapons/handheld (colour filters?)?

I've never seen a flashlight mod for ArmA or OFP that was worth anything. I doubt this will change - the engine's lighting method does not facilitate such things. Perhaps we'll investigate it more in the future, but right now there are better things to work on.

12. Is the item carrying system be changed at all? Can you carry more ammunition? What is the maximum you can carry? ie: 8 mags, 4 frags on a vest.

Yes, read the section in the original post about rucksacks. You can carry as much as you want/have space for (in the ruck, in cubic centimeters of volume), but it will have an impact on your stamina.

13. Any plans for a RTO, only allowing certain players to use certain radio channels?

There are ways to make an RTO useful, but there is no way that I know of to allow VON or chat to be enabled/disabled selectively. Perhaps in ArmA2. We will do something with RTOs, but it remains to be seen as to the specifics.

14. Any plans to change reload speed based on type of reload? Dry reload vs. tac reload? Any plans to add 31 rounds total after a tac reload? (For certain weapons)

Reload speeds vary based on stance, but there is no distinction between dry/tac reloads. Perhaps in the future, if it's worth the hassle. I'm not convinced that it would add anything - the difference in speeds is minimal in reality for a trained shooter.

15. Any plans for animations for using compass/map/GPS/watch? (Anything would do heh)

Nope, the ArmA animation system would make this an absolute nightmare and far more hassle than it'd be worth.