Ok, looks like they moved this to the correct forum and a few things got lost in the move.
The only oil you're using that won't disintegrate quickly with water is palm oil. I would drop the coconut to 20% as suggested, and shift it to palm. You could use part of that to up the castor by 1-2% if you want to keep the bubbles. If you're willing to use hard butters, you could substitute Cocoa butter up to 5% and/or Shea butter up to 10% for some of your (preferably) Olive or Canola oil. I've heard lard also makes a harder bar, but I haven't soaped with it, so I'm not sure which oils I'd displace for it.
Bear in mind that the more slowly your soap disintegrates/the longer it lasts, the less material it will give you per use to lather with.
Lather boosters, such as replacing water with Aloe Vera Juice or decarbonated beer/alcohol, or additives like sugar, sorbitol, or citric acid might be helpful if you find a harder bar cuts the lather too much.