Maybe you can have the best of both worlds Keira. If your MIL / bridesmaid / FSIL are set on a small bridal shower, you can consider having it as a brunch / supper so it's not super time consuming. This way, they still get to host something for you, and you can have the silly games / fun shower with people who will enjoy it and not be a complete buzzkill.
If having the one party with everyone there is important, you can always have the early part with everyone, and then the fun stuff after, so those who don't want to partake can bow out.
Totally agreed with autjo - people do get silly with this stuff, and inadvertantly create a stress on you when they shouldn't.