Regarding the free buttons (such as the Happy Birthday and etc) what are some tips to prevent from loosing them? I've nearly lost them a few times on my bags and I need some advice if possible!
I haven't had an issue with losing them, but you could put the pin through the bag and then put an eraser on the end before latching the pin so that if it does come loose, the eraser will keep it from falling off.
If I put them on my bag and I want them to "permanently" stay there, I use a bit of hot glue or putty to hold it closed. Both of those options can be relatively easy picked off, but of course means you have to travel with hot glue!