Yes, that will work fine. Just substitute, other things could be used too. I use coconut oil for a number of reasons, but they'll all work well (as long as you don't burn them). Check the boiling point on butter and make sure you dont go over that number, or even near it. A few more things.........
1. I made this recipe so you could travel with the gummies and they would not melt. I carry one in my pocket in a baggie for 4-5 hours and they don't melt- good as new. I keep mine in the fridge otherwise, if not over time, they will mold if kept too warm.
2. The stronger the weed and the more you use, the better the end product. For some, they are too strong and want me to use less or weaker pot in the ingredients. You'll have to make your own decision on this. Better to be a bit stronger and cut off a piece rather than have to take 2 to get the job done.
3. Some people just melt them in tea and drink the tea. It takes about 45 minutes or more to start feeling the effects, it really depends on how much you have in your stomach. START SLOW, I've had people freak on them- you've been warned. DON'T drive or plan on going out or getting much done. About the most I can accomplish with full effects is watching TV or playing my guitar or taking a walk- and sleep usually isn't too far off. I also recommend not smoking something or drinking, as these can make you dizzy and wobbly on your feet.
4. Adding the oil to the jello is always the last process towards the very end, again make sure it's well absorbed in the jello. Pour immediately into the molds when done or it will thicken and make pouring more difficult. I sometimes have to reheat whats left to make it pourable again, that's not a problem. Place them in fridge for an hour or two, remove from molds and put in tubberware in fridge. You're done...........
There are many recipes out there, I'm sure most are just fine. This is just mine, many are using it with good success. The final item will feel like a firm gummie, will melt in your mouth and taste great with no pot aftertaste.
One more addition- you don't need to have this boiling away thru the whole process. I often turn things down to medium to slow the process down a bit or go up and down. It won't hurt anything. If you use a rolling boiling thru it all, you'll get less gummies since a lot of water will be evaporated off leaving less product (but a stronger gummie).