For Giga Mac: Go to the side of the stage and try to cheaply throw him off the stage. It might take a few tries, but it's a no brainer.
For Guile: Start the battle with the Franklin Badge and keep your distance to Guile. You might start the battle with attacking Guile as soon as he appears to push him away from the center. The assist will rarely approach you and throw out his sonic boom things, which you will reflect and possibly hit Falcon with. That should buy you the time to deal with Falcon before the Franklin Badge wears off. It was kinda cheap with Dedede then because Falcon always ran into my jab again and again, no way he would jump over it. Otherwise, Falcon is still an obnoxious opponent in this battle, but Guile is practically taken care of. And since you've managed every other spirit so far, I'm sure you can do it.
Balder is a spirit that you should have gained. He appears either in that light&dark stage or somewhere else in the 2nd world, and can be evolved into a legendary defense spirit with Franklin Badge. I don't remember Guile's type though. Some support spirits bring a Franklin Badge, too, like Ana and some conductor guy (Mr. Tutori or something like that, I don't remember). But iirc they don't appear in the WoL so check the Spirit Board if you want to try it with them. It's imo the best way to approach this battle.