Oh interesting so Peter could be admiral in the Russian navy?Regarding portrayal of TTL Peter (gender-bent Feodosia) I imagine him as Navy-loving as OTL Peter (and for the same reason of inheriting estate of Nikita Romanov with its collection of amusement boats), but complete opposite otherwise, being a pious and in general sober person (Feodosia OTL was one of the most if not the most pious of Alexis I children). Regarding hobbies, not much is decided on, though possible artistic gift towards painting/drawing is possible (along with love of falcon hunting inhered from father).
Feodor, while being into military TTL, will retain his OTL hobbies of being amateur composer (in OTL some of church hymns he composed are still performed) & patron of arts/architecture (not to mention the falcon hunting which he was rather fond of OTL). Another weird hobby of him OTL was collecting singing birds.
And those interests seem quite eclectic aha