iirc android 7 allows you to use a microsd card as extra storage and you get to move your files and software in there. that should be a must if you end up wanting to use it
shattered pixel dungeon supports android 4 and up, and is a great game for passing time. really fucking good and should be low spec, it's just a pixel game in java maybe an emulator would work. most likely an nes emulator and if you are lucky, some snes or gba. would be cool honestly. try out lemuroid!
knowing the fact that it's old, keep an eye out on the apk version. if it's armeabi-v7a, goodie, it should work. if it's just arm64-v8a, then sadly it won't work
also, i know that k-9 mail was acquired by mozilla, so it's now the thunderbird program on android! try it out, it should work as well due to armeabi-v7 and the android 5+ system requirement :D
some apks won't install properly, so have "SAI" (split apks installer) handy. it worked on two of my android 7 tablets (if i remember properly) that i had to set up for my nieces