Hi Connor!
I'm about to walk my first Camino in August, but I feel comfortable answering some of your questions because I had some wonderful people from this site help me.
Flip flops- yes, pack them. Plus, you'll want to wear something open that are not your hiking shoes in the afternoons/evenings. So they can work as both!
Sleeping bag liner- yes, pack it. Most albergues will have a blanket, but it's good to bring something of your own that is treated for bed bugs. I'm taking a sleeping bag, but it's because I'm always cold.
Permethrin-anti-bed bug protection- no, don't pack it. Treat your backpack, sleeping liner & clothes before starting your Camino. It should be effective for 6 weeks. If you need more while you're walking, buy local.
More than 3 pairs of under garments- no, don't pack. 3 should be enough. Wear one, wash one & then the 3 is a back up.
Long pants & collared shirt- yes, pack them. You probably want to take 1 long sleeve shirt & 1 pair of long pants that you can both hike in & wear around town. If they don't function as both, them leave them at home. Having had a catholic upbringing, I know my mom would be mortified if I walked into a church in shorts & a tank top, lol. & my dad, who is basically a wilderness & outdoor expert, would always tell me it's important to minimize the amount of skin you are exposing to the elements if you're out there for a long period of time.
Mosquito Repellant- no, don't pack it. Pack a few repellant bracelets, or something small. You can also buy it locally if you get there & need it.
Rubbing Alcohol? No, don't pack it.
Compeed- yes, pack it. I am going to be taking a stick of Body Glide & using that on my feet daily. I've been told prevention is best & that it works, so I'm going to recommend it to you.
Keep your first aid kit small & ultra basic. Spain pharmacies & stores will have anything else you need.
Hope my suggestions help! Enjoy your journey!
