Of course you can replace the Shea butter with something else. Just make sure you use a
lye calculator when you make the substitution, because the amounts of lye will change with different oils.
Do you have access to Cocoa Butter? You could use 12% Shea and 8% Cocoa Butter and still get a hard-ish bar with a little more longevity. Are you sure your olive oil wasn't pomace olive oil? Pomace speeds trace quite a bit for me, so I don't even use a stick blender when I use it at 50% of the oils in a recipe.
Heat does matter of course, but at 100°F doesn't seem too warm for your recipe. Maybe you used the stick blender too much. If your OO is regular (EVOO or light OO or whatever else you have available in India) and NOT pomace OO, then I would use the stick blender very minimally. Short bursts, for only 3-5 seconds, followed by hand stirring, then once you get it to emulsion (no oil floating on top of the mixture), avoid stick blending altogether.
Once you get the hang of minimal use of the SB, then you can stat to consider swirls and whatnot.
It is TOO SOON to start your business, if your business plan is to sell soap. You need to learn to make a consistant product first AND you need to KNOW how your soap performs over the course of a year, and that it will be safe to use and will not go rancid over time. So keep making soap and watching and evaluating it for a year, then re-visit the idea of starting a business.
One other question: Did you use any fragrance in that batch? Some fragrances also contribute to speeding up trace, so that is an important component to your formula. If you did use one, please indicate which one and the manufacturer. A good source for Soapmaking Fragrances lists information about how each fragrance performs in soap (acceleration, ricing, discoloration, well-behaved, etc.), so always look that up for each fragrance you purchase.
