It'll be a different consistency, but sure you can do it. No problem. Some people say you can sub liquid oils for liquid oils, and sub the ones that are solid at room temp for other solids if you want to stay close to the same consistency.
One basic lotion recipe I completely forgot about because I haven't made it in a while is: 1 part beeswax to 4 parts olive oil. That's what I do with the end bits of our beeswax candles. I usually add a little Vitamin E oil or jojoba oil to the equation, but whatever the oil blend is, I keep the overall 1:4 proportion the same. It's a great little recipe for small batches.
I never fool around with a double boiler. I have one of those cheap $5 mug size hot plates and I put a glass measuring cup on it and melt the wax in that. It does take a while to melt, but I just keep an eye on it while I do other things. To be honest, I just dump it all in a food processor (that I never use for food prep) with a few drops of lavender oil if it's for me, or frankincense, sandalwood and myrrh if it's for my husband. For a small batch, I just add the 4 parts oil in the measuring cup and blend it with an immersion blender (that I never use for food prep). I use a little foil, wax or parchment paper to make a "lid" to make sure I'm protected from hot wax splatters.