Ooh Robin!
OT: 1. Robin, Tashigi lacks the strength to overpower Robin's DF Power, unlike Zoro or Sanji. It can be noted though that Tashigi possesses Armament Haki while Robin does not.
2. Haven't seen Hina Post timeskip. Not sure. I'll go with Hina though.
3. Hina. She has higher rank, that alone should explain the difference in power.
Hina would be interesting. Her power locks limbs or things she contacts. However Robin can produce replacements.
The question would be do limbs sprouted on Hina get tied up. Though at the same time one could ask how many limbs can Robin sprout on Hina... Since if she places too many locks on attached limbs... Hina would immobilized herself by the weight of chained Robin limbs.