In the PHB, Expertise (double proficiency on skills) was limited to Rogues (any skill or Thieves' tools), Bards (any skill), or Knowledge clerics (knowledge skills). These feats dilute that niche. That's a problem, especially for Rogues, who now lose the ability to specialize through these skills (in that their benefit from the feats is smaller than another class).
While it is not spelled out, the only way to preserve the niche held by these classes would be to allow the expertise granted by these feats to stack (i.e. to give triple the proficiency bonus, not double). That will bend the limits of the game, but would help keep the rogue and the knowledge cleric distinct. (I am not sure the Bard needs more benefits).
Since all of these feats can grant expertise as well as +1 to a related stat, all of them end up more powerful than a feat such as Skilled. The third bullet point, then is gravy on top of an already strong feat.
I can't help feel many of these will be appealing to players, and that part of the reason is that they are all strong. I can think of cases where I would take these even without the bonus to the associated ability.
I will say, I think they have balanced the feats that grant spells (or, better as [MENTION=6798775]Ath-kethin[/MENTION] suggests, spell-like but nonmagical abilities) well: iI still suspect the bonus to the relevant stat is too much -- expertise on a skill and a 1st-level spell (and in three cases a multi-use, flavourful, but non-damaging cantrip), should be enough for a full feat; still, they have constrained the choice of first-level spell and limited the available cantrip.