Your batch that riced and seized was most likely caused by the FO and/or temperatures (Strawberry can be a real bugger)...the sunflower oil should not do that if it is a small percentage of your recipe. Did you run the recipe through a lye calculator?
If you are trying different recipes, slow down a bit and find one recipe that works well for you and expand on it with colors, additives, fragrances and etc. I like using sunflower oil or grapeseed oil....try one of these and see how it works for you:
2 oz GO or Sunflower 9.09%
2 oz Castor Oil 9.09%
2 oz Shea Butter 9.09%
8 oz Coconut Oil 36.36%
8 oz Olive Oil 36.36%
3.121 oz Lye
6.336 oz Water
Buttermilk Recipe:
28 oz Olive Oil 65.85%
10 oz Coconut Oil 23.53%
2 oz GO or Sunflower 4.71%
2 oz Shea Butter 4.71%
.5 oz Buttermilk (powdered mixed with distilled water, add to warmed oils) 1.18%
5.847 oz Lye
11.871 oz Water (discount by the water used in buttermilk)
(this makes approximately 53 ounces)
Also, you can try soaping closer to 100 F degrees...try to stay at 100 - 105 with both oils and lye. See if that works better for you and gives you more time...just remember that trace takes a bit longer at lower temps.
Hope that helps....if not we will try again as I have plenty of recipes and ideas