Martin,I am still using Google Nexus 7" gen 1 with just 16Gb of RAM. The 32 GB model would be a better choice because I do occasionally have to clean out redundant files as I start to run out of RAM. The Nexus works well and I can't justify changing it. I only ever use the tablet with the P4 and it fits perfectly in the front slot of the DJI foam case which I have fitted inside a backpack.
Whatever you chose as your monitor the most important thing is to fit a non- reflective screen protector.
All the best, Martin
The iPad mini works really well with my Phantom4 Advanced. Only drawback is that I wish the display was brighter.DJI flys well with Apple products. I have a 2014 I pad air that still works well. DJI focuses on Apple products because it is one system, while android has many systems to cope with.