Could they be planning a surprise shower? What I would do is talk to your mom, perhaps, and tell her that your friends are having a shower for you in your town and you're wondering who you should invite from the family. Don't mention a famil yshower. Just play it from a 3 hours is far to travel, you don't want to seem gift grabby, but yet you also don't want to upset anyone by not inviting them.
From this- your mom might say "Oh - a shower is being planned" - or... something to that effect.
However, while your friends asked for a list, at the same time, talk to them more about how many people THEY can afford to host. They may be asking you for #'s, but thinking 10 people, but if yo uhand them a list of 35, it might be more than they cna handle.