waterproof, color and KOReader

[eatthedishes]

I am searching for an ereader mainly for reading epubs, but also the occasional pdf (and maybe audiobook).

• waterproof - i want to read in the bathtub (my kobo aura h2o was great for that)
• color - i ocasionally want to read pdfs with graphics
• KOReader compatible - also for pdfs (that worked well on the kobo aura h2o)
• no forced account - i only want to sideload
• physical buttons - also helps with reading in the bathtub

I have found two devices: "Kobo Libra Colour" and "Pocketbook Era Color". Are there others that would fit? And which would you prefer?

For the Era Color an advantage seems to be the speaker (for audiobooks); for the Libra Colour the option to use a stylus (for annotations in pdfs, i did not see that option for the Era).

The only thing I would consider an account for would be the pocket app to download news articles. Does this work well for everyday use? (Seems to only be available for kobo.)

Since these readers can process audio, can they play "slow videos" with audio? I am thinking of videos that just show a picture every few seconds, basically like powerpoints.