I believe that orchid mixes are typically based on bark. You can probably get incredibly detailed instructions at the orchid forum.

The Miracle Gro cactus soil, and almost every other cactus soil available in the US, is based on peat. Commercial cactus soils also never provide sufficient drainage for real succulents and cacti. Your own Cactus soil sounds much more suitable, except that I would add something coarser like grit or perlite. The Orchid Mix will eventually break down and you will be left with no drainage, so you should plan on repotting at least every two years if that's what you use.

Easter Lily is one kind of plant & Easter Cactus is another, pls. clarify exactly which plant you're asking abt. This is why botanical names are best (when one knows them), it helps to weed through this type of confusion.

I'm not trying to sound smug, but Easter Lily Cactus sounds unlikely to be correct as Lilies & Cacti are VERY different plant families which require very different types of care & soil.

It's called Easter Lily because it blooms around easter-the flower resembles a Lily flower i guess.
shrubnbulbs is right about peat and cacti.But,mostly we are stuck since almost all, if not all, commercial mixes use peat-while large growers of outdoor plants and botanical gardens never use peat in their mixes.
And peat mixes over time are bad.Eventually they breakdown into a bog, smothering any plant in it.For the short term they work great-the paradox.For plants to be eventually planted in the ground, peat is ok..for permanent house plants it is the proverbial silent killer!

Echinopsis has the common name of "Easter Lily Cactus", because of its large bloom, and the tendency to bloom in the spring. It seems to do well with with a slightly richer soil mix than many other Cactus. An easy way to improve drainage and aeration with the commercial mix is to work in an equal amount of perlite. Good growing to you!
Ray

Thanks to all who replied. It is also my understanding it is called Easter Lily cactus because of when it blooms and that is the name on the card from the grower Monrovia. Mine had just bloomed when i bought it but it has not bloomed for me although the cactus is doing really well. It has gotten much bigger and is producing many many small "pups". It needs a bigger pot now I think. Someone suggested it needs some cold temperatures in order to bloom. I kept it in the house over the winter because it sometimes gets down to freezing here in the winter months. I am trying come up with a different strategy for this winter.
And it looks like I will need to change the soil composition too.

Does anyone have any suggestions on how to manage the re-potting of Cacti? I am wondering about all those sharp needles and how to avoid being punctured many times over. Can you wrap something around the top of the plant?

Echinopsis aurea will do fine with occasional freezing temperatures, provided it is kept dry. Mine survives winter with temperatures down to the low 20's. You should be able to do better with lower humidity, more sun, and better daytime temperatures.

The old method is to fold newspaper into a band you can wrap around the cacti. A folded towel+ gloves gives a better grip i think.