By RAW alone, it seems to be **yes** to both questions.

[Sneak Attack][1]<sup>DDI</sup> is defined in terms of weapons alone: you can deliver it when hitting with a light blade, hand crossbow, shortbow or sling; but it does not explicitly limit the usage to **Weapon** (keyword) attacks only.

About [Surprising Charge][2]... I don't have access to the rules right now, but if I remember correctly, the 1[W] notation isn't tied to the Weapon keyword. So, charging with a implement-based MBA wielding a dagger-as-implement should grant the additional 1d4 die of damage.


  [1]: http://www.wizards.com/dndinsider/compendium/class.aspx?id=719
  [2]: http://www.wizards.com/dndinsider/compendium/feat.aspx?id=416