Fine tunning a Rapsberri Pi 2 B+ full 0.12 node
You do need to store data on an external SSD disk (USB). 

If your data and swap are on SSD media, you can use all those options (they won't matter much).

I don't recommend to use Pi 2 (any version), it's a waste of time. It can barely keep up, it becomes useless for anything else and each time you restart the OS or bitcoind you need to wait several hours for it to catch up.