Several things here:
1) I've never used Spotify so hopefully
@August_West can give you tips on that.
2) Password management - get lastpass.
Link. Anyone not using something like lastpass is silly. From the research I've done, it's usually the recommended solution. Lastpass is free and you can start with just a couple things linked to it and as you get comfortable, move more stuff into it. Only downside to it is having very strong 15+ random character passwords gets a little difficult when you have to use them manually on non web page (ie, phone apps). You can pay $1/month for mobile support but the apps still really can't be used directly - I didn't see the benefit of the mobile support when I did a free trial.
3) For photo storage I use Flickr. I set it up 5 years ago when I got back from a Hawaiian honeymoon and had a couple thousand photos to store. At the time I did some research and it was one of the few that stored the full resolution. I'd be that's changed for the others and everyone does now. I don't think you can go wrong with any of Flickr, snapfish, photobucket, dropbox, etc. Just make sure you are diligent about uploading photos instead of putting it off like do.
4) Hope you didn't take offense to me describing you like my Dad and the difficulty of explaining IT to him. You are more advanced than that, but it was pretty clear you weren't in the category that should be setting up a home NAS or programming a raspberry pi. A raspberry pi is for kids with too much time an not enough money to buy purpose built hardware. A NAS is for a geek like me who likes to deploy random hardware that I never use. I don't even want to tell you about the new workstation I'm about to build to browse the web with. NASA could use it to find life on another planet - but it will be a fast web browser.