I never had the Wii version, but I do have the PS2 version which is a port of the Wii version. I also have the 360 version of 1 (Ultimate Sith Edition) and 2.
Graphics are obviously better on 360 and well as more interactive destructive environments. Wii version's graphics aren't as good, but the gameplay is just as good, and at times even better than the 360/PS3 version. Starkiller has more powers on the wii version like Force Choike and Sith Rage that isn't on the 360 version. 360 has DLC of Tatooine, Coruscant and Hoth levels that isn't on Wii, but this DLC is pretty expensive compared to the actually playing time of them, 10 bucks a piece. You best bet would be to find a Ultimate Sith Edition if you can since this has all the DLC included, you could probably find a coverless copy on ebay for about 20-30 bucks, which will save you money compared to separately buying the DLC
Wii also has two exclusive missions that take place in the Jedi temple, and IMO these have more value than the 360 DLC missions, both levels taking about 45 mins to complete. Both 360 and Wii have extra costumes and player skins, but you have to pay for the 360 ones while the Wii ones are just activated from a cheat code.
Most important feature for you is because you have multiple kids, this is why the Wii version might be better for you since it has a multiplayer VS mode that 360 version doesn't have. Multiplayer mode is a 1 on 1 battle mode that two players can choose different jedi and sith to fight with and duel it out in a soul calibur style fight.
As far as FU 2, I'm currently playing through that one now, the gameplay is without question improved and fun, but the story is just all over the place.
