I started binge watching Star Trek Enterprise. One problem is that every time Porthos the beagle shows up I stop caring about the plot of the current episode. I just want to cuddle him and give him some cheese.
If Porthos is not seen in the Mirror Universe episode, I assume this will be the catalyzing that turned Starfleet evil. Also, given the general tone of Star Trek and how the main characters all have plot armor. I'm pretty sure Porthos is invincible. It would obliterate the tone of Star Trek to have a cute dog die. So you, I'm sure it will happen in Star Trek Discovery.
I do not speak Dog Sign Language, but I believe I have translated this. The first picture "okay" and the second is "fuck yeah!"