If defensive units land in the village on the same second as the attacking units, what happens? Is there a battle or do the attacking units attack the village as if the defending units have yet to arrive or does the battle take place between the attacking and defending units?
Also, if there is another wave just a second behind the first attacking units, I'm assuming that the defending units will most definitely engage with the 2nd wave if not the first since it lands a second later after the defending units arrive?
This is actually an interesting subject, at least for me.
When World 1 opened here on .US there were a lot of TW1 veterans who were taken aback by the lack of milliseconds and the forced +/- on march times. We did a lot of experimenting and a lot of things have changed between then and now, but on this subject explicitly what we discovered was as long as discipline is equal that the game rounds the landing times to the nearest half-second and then randomly picks from the array of actions landing to determine the outcome.
For a bit we thought the landing order could be manipulated client side because if you refreshed your page the landing orders would be shuffled, so there was a lot of refreshing to try and get the correct order. We came to realize this was completely handled by the server and this was just a client side visual representation of each array.
Later it seemed that Inno thought this was inadequate and added tags to their array named something like offense, defense, or transferred and if there is a troop movement labeled as defense or transferred in the .5 second block it will try to pull one of those before pulling the attacks to land in the same block.
TL;DR:
If there is a difference in village of origin discipline that takes precedence.
Assuming all things are equal, landing troop movements are rounded to the nearest .5 seconds with an initial preference (but not a guarantee somehow?) of defending units and transferred units within the same .5 second block as the incoming attacks.
If there are any troops within the village at the time of an attack, all the troops in the village will participate in its defense.
