49 Days til Germany!

My son has been accepted to a study abroad program in conjunction with his university and will be spending about 8 weeks in Germany this summer.  Of course, that means I really *need* to go with him!!!  Well, okay, just for a few days (10 days) ... I haven't been back to Germany since March of 2012 when my son and I went for Spring Break.  I am way past due for some time in the Old Country!  AND I am taking my oldest daughter with us as well ... she has never been to Germany.  We can't wait!

As a child, I spent every summer in Germany with my grandparents ... and I guess I took for granted that I'd marry an American and make my life in the USofA - and no longer enjoy those yearly trips.  Granted, my husband and I were stationed in Germany for 3 years with the Army, but even that was a long time ago.  Over 20 years ago ... we are old!  

I feel like air travel and international travel in particular has changed a lot in recent years -- and especially since 9/11 (2001).  I used to be a pro at packing suitcases and picking out my carry on items to take on the plane ... but now I am attempting to read the tips on the internet to figure out what to take with me.  My goal is MINIMAL and DUAL-PURPOSE!

Back in the day, I was allowed 2 suitcases on my international flights - at NO EXTRA CHARGE (imagine that!).  There were weight limits, but otherwise, I always took the biggest, sturdiest suitcases with me on my summer trips.  Now-a-days, you can only have 1 bag (at least on the airline we are using) - and our domestic flight (a different airline) will charge $60 for a checked bag.

I get it that I'll have to pack travel-size shampoos and such like if I carry them on ... and I realize there are a few other things I will have to consider post-9/11 security guidelines.   The last time I flew just within the United States, my carry on was selected on both my to and home TSA checks.  I had peanut M&Ms in the one incident that they were very "suspicious" about ... and the other one, I'd forgotten that I had a full-size beauty product with me ... and I felt like a reprimanded child.  My palms were swabbed for some reason ... and some sort of magic powder was put into my bag by the agent to check for some unknown substance ... I sure don't want to go through all that again!

So far, I'm thinking I want a backpack for my carry-on (leaving me hands-free), and I will take a small, cross-body purse that I will use while we are in Germany ... but otherwise, what else do I need??

So far, on the list for my carry-on:
ear plugs (or noise-canceling headphones)
a good book
maybe an eye mask (for sleeping)
I always take a toothbrush and travel-size tooth paste tube to freshen up before landing
along with some touch-up make up
Snacks - but what kind??
tissue
and I always fold up a Walmart/plastic bag and stuff it into my purse - weird but I have found it useful

We are staying with relatives for most of the time (and have an Airbnb for 2 days) so I have access to laundry facilities.....clothes won't be an issue.

WHAT ELSE???  What must I take?
Electricity converter (I have a travel one)
Battery charger (for cell phones & devices)??

I need your best recommendations for what to pack ....
ALSO, what should I bring the relatives as a little Mitbringsel (memento or keepsake as a gift)?

HELP!