Thomas:
(1) I've done both. If it's early on and I've got a long day and miles ahead and don't much like hiking in wet socks and shoes, then I may switch out and cross with my Crocs knockoffs. OTOH, if I know it's just a few crossings and camp isn't all that far away, oh heck, I just cross. Some people say they get blisters hiking in wet shoes and socks but I don't. YMMV.
(2) Again, personal preference. But to me, the two things that just belong outside your pack are: your rain gear and your tent/tarp.
Think about it: say it's raining hard…
(1) When you arrive at camp, you can access your tent/tarp without even opening up your pack and exposing the contents to the rain at all!
(2) When it's time to leave, you can pack up in the safety of your tent/tarp. Once the pack is nicely / safely closed up, you can then put on your rain jacket, take down your tent/tarp, attach it to the outside of your pack — and be ready to go.
But if you insist on packing your tent inside your pack, then at some point, you will likely expose your pack to the rain — not to mention how packing a wet and muddy tent/tarp just makes everything else damp inside (humidity) — even if you physically isolate with stuff sacks and such. Makes no sense to me.
Some folks are concerned about getting their tent sack torn up if attached to the outside — but I just haven't had any problems with that at all. OTOH, when shopping for a tent, I do look for compact-folding tent poles — like my beloved Seedhouse 2 SL — so things don't protrude out to the sides. Again, YMMV.