I agree with the fact of having to commit to a party would be pretty lame. I also agree with there being no real reason for companions to die at the END of Act 1; however, I do feel like the tadpoles need to feel like more of a big deal in the game as of right now they just kinda feel like they are there and have no real purpose other than to give you special powers. To make them feel more threatening they should turn one of your companions and I feel like the end of Act 1 is the best time for it to do so. If this isn't the case perhaps if we do actually get them removed(idk if this happens yet, idc if you spoil it doesn't matter I am going find out sometime anyway) someone dies during the operation.

People dying triggers an emotional effect on people whether it being anger and forcing pursuit for vengeance for that person or sadness that you lost a friend, either way its good for story progression. I think this should be something the DM(Larian in this case) has control over and not us. We just are not allowed to lose character created people and only being able to lose companions. I do not have a great solution and of course we are all spit-balling opinions so this is mine.