I think the same like Charly.
Many from us are waiting for the next big and great patch (LOS display from each hex, orginal graphic like the board game).
The game is amazing and will be even better.
1. How hard is it to make a map for a scenario? (I have enjoyed ASL in the past and I see people have made conversions recently.) Is it just a case of picking say level 1 Hill tiles, ground level tiles, then some building tiles?
The designing is easy but I have no idea how difficult it is to write an AI script for singleplayer. (ok the game is anyway more multiplayer than singleplayer)
2. Will there be factories and multilevel buildings later in the game?
I know the maps from the next expansions and there are no such buildings. Of course you can build villages with many houses. But there is no city or factory titles yet. I also think the rules does not care about this things, but don't be afraid, the rules of the board game are still growing (night chart, plans, cavalry, beach landings, etc.).
3. In terms of playing live do some players play a scenario over a few evenings? I ask as I may not be able to do it all in one session. (Bummer that PBEM is not possible).
It depends on the scenario. I need from 1 hour for a very small map to 6 hours for a huge map. You can save and load the game, no worry. And the game system will not work with PBEM because a "turn" is only one action. The game has no downtime for one player!
4. I enjoyed ASL campaigns very much, Red Barricades, etc. Are similar type campaigns in the plans, i.e. large map with destructible terrain that would carry over to the next campaign date along with surviving units? (I am not interested in campaigns that follow a certain unit through the whole war.)
I have no idea about this. I think the official support for campaigns are missing.
To find people for multiplayer ask here, or in the ingame forum or in the facebook group.