When I successfully maintain a grapple with Telekinesis, if I want to use the 'attack' action what would my damage be? I'm leaning toward 1d6 + Int/Cha, but there really is nothing to help indicate it. One could argue you can't, but I'd argue you can contort someone's body in very painful ways until you twist them into an unfortunate mess.
I'm guessing for the 'move' grapple action, you can move them 10 feet (half the speed you can move an object under the 'Sustained Force' version of the spell.)
The spell really doesn't have enough writing to explain. Since "Crushing Hand" exists as a separate spell, I don't think telekinesis is intended to let you damage the target, but it doesn't explicitly say so.
If we assume that you aught to be able to damage the grappled target as you would with other grapples, then you'd use unarmed damage unless you had one of the other weapon options available.
This brings us to another branch though. The spell doesn't explicitly say that a grappled target is grappled in place rather than being moved adjacent to you as they would be if grappled normally. If they are moved toward you then you'd have any of those listed weapons as options if they are available to you. If the target is grappled in place and not moved, then we'd use the weapon options that the spell has available to it, and it's only damage option is "hurl", not one of the listed options.
Other grapple options have similar problems when you "resolve these attempts as normal". Can your telekinesis tie someone up with nearby rope? If you use the move option do you use your move or the spell's move from the sustained force entry? Do you gain the grappled condition while grappling with the spell? Can you use your constrict damage in conjunction with the spell? The spell is a mess.
For ease of use, using the 1d6 hurl damage as if it were a natural attack for damage in a grapple seems fine.
Pure rules as written. When you use the spell to grapple, they are moved adjacent to you and you both gain the grappled condition, you are then grappling them as normal but your ability to grapple is augmented by the spell allowing you to use your caster level plus casting stat as your CMB. You must make concentration checks (DC 10 + the grappler’s CMB +5) each round due to being grappled or lose the spell. I don't think that's the intent at all though.