1. The mold you are using holds the moisture in the bottom & side walls longer than some other molds. I think it's the nature of the material. Any recipe I use seems to take longer to harden up in that type of mold. Give it several more days to a week. Don't try to unmold until the exposed surface feels like hard cheddar cheese.
2. Individual molds inhibit the gel phase without the help of insulation or CPOP. The batter cools off very fast in individual molds. How warn/hot was your batter when poured? Did you insulate or CPOP?
3. If you didn't apply a mold *release agent to the mold, place them in the freezer for about 15=30 minutes prior to unmolding. Let sit on the counter a bit (no more than 5 minutes) & gently attempt to unmold. Sometimes running warmish water over the bottom surface (of the mold - don't get the soap wet) can help release it if it's tough to get out.
How can you avoid this in future with individual molds?
1. Re-evaluate your formula, including the essential oils used. 8% SF, with 60% soft oils, with 4% EO, 30% lye concentration - all may have contributed to the slow set-up time. (I'd at least change the lye concentration to 35% with this much olive oil.)
a. What essential oil did you use? Did you look up safe usage rate for that one? 4% for some EOs might be a little too much. Some can affect set-up time as well.
b. In place of sodium lactate, you can just add salt to your recipe; just a little. SL is fine, but if you want to try this before the SL arrives, just dissolve table salt** in hot water (deducted from your lye solution water) & add it to the oils or to the lye solution. It does the same thing as SL.
2. Re-evaluate your process. Heat & thickness of batter when poured affect how fast the soap cools in the mold, especially in individual molds. Insulation and CPOP help promote gel or at least heat retention to speed set-up.
* mold release agent (I use either lanolin or Vaseline, but you can use mineral oil)
** 1 tsp table salt ppo