Sounds good but considering the 3teFK level and their attendance (no offense intended), wouldn't it be better to move 92nd to League 1 and 3teFK to league 2? I think it will make both leagues much more interesting. Perhaps also see if you can move 5pp to league 1.
Well the original Leagues should have been done on attendance not whoever signed up first, as size is generally indicative of a regiment's longevity and skill level, and that way the larger regiments would not have to sit half their line in spec while playing tiny regiments in League 1, but it's a bit late now.
Unless some weird play-off system is arranged to allow a 3rd league team of getting directly into the 1st league (e.g. 3rd place League 2 vs 1st place League 3, winner gets to go 1st League), any good teams who were in League 3 are just going to have to wait a couple seasons.
As for the Champions League format, round robin would be best determiner of the 'best regiment', however I would not mind a group-stage followed by knockouts like the UEFA CL do it, it would make this winner's tournament different from the league and perhaps more interesting. You could have two groups of 3 regiments, top 2 from each group go through to semi-finals and then a final.
To make the groups fair based on their league positions they'd be like this:
Group 1:
League 1 1st place regiment
League 2 2nd place regiment
League 3 1st place regiment
Group 2:
League 1 2nd place regiment
League 2 1st place regiment
League 3 2nd place regiment