Island Sanctuary Visitors Assistance

So, friends and FC members can visit each other's sanctuaries. But, why bother? I mean, we can't interact with their island, we can't help them progress, and we can't share or, better yet, trade, our gathered materials.

What if:

Make visitors able to gather materials to contribute to island progression. Maybe, as an incentive, they can earn a mild amount of cowries after gathering so many resources for a friend.

Once my island is kind of in a waiting mode and there's not much point in my sticking around gathering a surplus of materials, I'd love to be able to pop over to my friends and FC members islands and help them progress. This adds a fun little coop aspect to the island sanctuary.

Furthermore, accessibility being restricted to friends or FC members being logged on. Making it so we can help out if they aren't able to log in. We can pop in, tend to their pasture animals and their crops. Again, coop.

Lastly, what if we could trade resources with each other? More coop.

And, as a fun sidenote, retainers being present on our islands.