No matter what you do, just bring a little zip lock bag for your electronics for each person.
It's one thing to have a poncho, umbrella, or nothing at all. You can still can get wet in the process depending on how hard it falls and the wind. The only thing I care about is making sure I do not lose my phone due to it getting to wet. If I get wet, if anything else gets wet, so what? It will dry. Even when it comes to having them in a backpack, or purse I wouldn't risk it. It can soak through, or the opens of a purse can expose electronics to the elements. So, unless you have it in a plastic backpack I would bring zip locks.