Why we can't look at the next wildling card when we have the power of the mesenger raven and we didn't trade a order

because different wildling cards are not implemented yet. Wildling attack always leads to return of HC if Nightswatch wins or elimination of units when wildlings win (4 Mustering points for lowest, 2 for everyone else). See this thread for the implementation progress: https://www.thronemaster.net/?goto=community&sub=forum&fid=5&tid=270#top

Also you might take a look at this threat for further differences between the 2nd edition and the edition played on this website: https://www.thronemaster.net/?goto=community&sub=forum&fid=4&tid=3737#top