every rose fragrance that i've tried has always seized up on me before I could get it thoroughly blended. do you think if I added it to the lye/water mix and used it as part of the saponification process it might help with the fragrance blending or cause some sort of disaster?
How much fragrance are you using? A rose fragrance oil that is tested should not seize. If it does, I would expect not compatible with soap or excessive use.
I had trouble with a floral-scented fragrance oil seizing to the point that I had trouble getting the soap out of the pot and into the mold. I really liked the scent, so the next time I made a batch, I melted and blended my oils, stirred my lye mixture in and, instead of using a hand blender to bring the soap to trace, I added the fragrance oil right after the lye mixture. After just a few seconds of blending the fragrance in by hand, the mixture traced but didn't seize. I added calendula petals and poured it into the mold. The soap turned out fine. You may want to try this with your rose fragrance oil to see if it makes a difference. Hope it helps!