Thank you for the suggestion. Done.
Done.
Limiting the feats to skill-related would either make work for the DM (if I left it to the DM to decide which feats were skill-related) or leave odd gaps (because a source I don’t have which the DM uses has skill-related feats). For example, by the wording you suggest (“feats that grant bonuses to skills (or feats that have such viable feats as prerequisites)”), Track wouldn’t be a Crackerjack bonus feat.