Whether or not I'm cleared to start writing, I took the liberty of jotting some questions down that might be useful to you all. I apologize in advance if this is a bit, ah, overwhelming, but I think these are some fairly important things to consider before jumping straight into a setting like this.
1. To what extent are Pokemon capable of cross-species communication? You mentioned considering the idea of a device that would let humans understand them (if it comes down to a vote, I'd actually rather this not be a thing), but beyond that, how well can they "talk" to each other outside of obvious like species (ie: two kinds of canine)?
2. What's the stance on Ghost Pokemon as a whole? For instance, can they actually become intangible at will and disregard physical barriers? Does the Regime have a means to contain or control them?
3. What are Psychic Pokemon capable of? Can they actually read minds, communicate via telepathy, and so on?
4. Are Dark types actually immune to the influence of Psychic Pokemon? If other Pokemon can be detected psychically, are Dark types vulnerable to the same forms of detection?
5. Is Pokemon battling still a competitive, likely sponsored, sport?
6. How does the resistance communicate with its members? Is there any command structure at all, or is it more of a shared ideal than a true faction?
7. What qualifies a civilian for ownership of a Pokemon? How common a sight are they in the care of regular people? (My assumption here is that only relatively harmless Pokemon could ever be legally owned without special rights granted to VIPs in need of protection, soldiers in the armed forces, etc, but can a Growlithe be an ordinary person's pet with the right permits, for example?)
8. Given that this is a draconian regime, what's your everyday police officer equipped with?
9. On a similar note, has the country's transformation into a dictatorship and the subsequent loss of personal freedom and privacy associated with that had any impact on criminal organizations or particular forms of crime? Just as examples, smuggling (and of what?), drug trafficking, or extortion rackets.
10. Under the assumption that Pokemon exist in place of real-life animals, am I correct in assuming that animal products such as meat, fat, and leather still exist in the setting and are provided by butchering (relatively unintelligent) Pokemon? Furthermore, and disregarding how cruel the Regime's policies may be in this regard, is the fundamental act of butchering animals for these products tolerated in-universe and among the rebels in particular? This one's kind of a big deal for anyone thinking to have a carnivorous Pokemon as a partner.
Sorry again if that's a lot to consider all at once.