It is best to take off as much of old soil as possible - leaving it defeats the purpose of using different mix - at least to some extent. It is recommended to add 'generous amount of perlite, 50% or more' - I think you did well :) You could grow succulents in pure perlite, or pure pumice, or pure grit (or some other inorganics) - they all provide good drainage and aeration. Some bags of perlite have lots of dusty fines, so it may be good idea to sift it. I use a kitchen sieve to do that, putting all sifted perlite into a container with warm water (most likely it doesn't have to be warm, just the way I do it) and rinse it. Then I strain water using same sieve and use it. If I was to use the mix you mentioned, I would sift it too; most often there is still lots of fines in the mix. You should check if there is list of ingredients on the bag to see what it contain. Too much of organic ingredients may attract bugs like fungus gnats since they like wet organics. Not saying you shouldn't use it thou :) Many ppl. use this mix, just have to be careful about watering (that's why addition of perlite-to make drainage better). Personally, I don't buy it since I don't really see any benefit using it for succulents.

You can keep them in that container, but you're going to have to be a lot more careful than you would in a more traditional environment. A couple things. - Pink isn't always bad! Quite a few succulents can develop a pink tint around the outer rim of their leaves when they get a lot of sun, however, be careful of beige, brown, black, grey, etc.. The difference between a healthy and happy pink and an unhappy color is pretty obvious when you see it. - The rocks are a dicey move. To keep the container I'd recommend switching the soil to a well draining cactus soil and mixing in some of those small rocks to give it extra drainage. Without a drainage hole in the bottom you're going to have to be extremely careful to not over water, too. - Like Lena said, succulents need really good drainage and air circulation, otherwise they're going to rot. These plants are built to survive droughts (but they are not cacti - under watering can cause harm as well). The way they do this is they suck up and store all the water they possibly can. Too much water means they will bloat up until they pretty much turn to jelly and die. If you lived in an arid environment and payed very close attention to these guys, you could get away with this container, but still probably not worth the headache. - That container is great for other things! Especially if you really like the rocks you could consider putting a big air plant in there (as long as you're good with regular care). While it can be done like this, wouldn't it be more fun to increase your number of plants and give each one a container they'll truly thrive in, without a lot of headache? - Ditto to Lena, again! Looks like Echeveria varieties. Of note, these are ones where some healthy pink / red around the outer leaves might not be bad. The one on the right might be Echeveria Halbingeri and the one on the left might be an Echeveria Huffs Pink or Blue Cloud. These plants especially like full sun (careful of burning from intense afternoon sun, depending on where you live), and if they get enough sun you may notice them turning a healthy rosey around the edges!

I am not sure what is wrong with them and would hope someone smarter than I will come along and help out. Not sure if it's a disease or growing conditions not right. But I will tell you that these plants need a fast draining potting mix, and commercial cactus and succulent mixes are most often too water retaining. Remember these are succulents, they hold a lot of water in their leaves and suffer if they are overwatered or in soil that holds the water too long or even dries out and resists water. The best practice with succulents is to have a fast draining soil, and when the plants are dry, water until the water comes out the bottom of the pot. If you want to try to save them I would suggest mixing your cactus and succulent mix 50-50 with either perlite or pumice available at nurseries here, not sure what's available for you there. Both pots need to have holes in the bottom so you would want to replace the one without a hole. If you do a repot and notice rotting stems, the plant probably won't make it.

Is the soil wet? If it is (wet), pull the plant/soil out of the pot and expose it to the air. If it's /dry/ then take it to the sink and fill the pot with water and wait for it to run out the bottom. Tell us what it does, does it go around the edges and almost immediately exit the bottom holes or does it seem like it's taking it a while to exit?