Hi fq author here and also acquaintance with the gnu poke author. One difference is that fq is focused in decoding and querying while poke might be more focused on editing and runtime modeling of formats. But we have both inspired each others think.

Here is video of me demoing fq and talking to jose (gnu poke author) about it https://www.youtube.com/watch?v=GJOq_b0eb-s he also organized the FOSDEM binary tools track.

No idea. But i know poke has a rather big community