DaisyI said:Hi Sabi,
They are succulents so should be planted in cactus and succulent soil.
Bonsai is a pruning style and can be done with any plant. To be successfull, you need patience and your plants need time. I'm not sure what 'bonsai accessories' are.
What you want to do right now is provide light and care to grow sturdy, chubby stems with closely spaced leaves. Leave them in the pots they are currently in and wait for a year or so until they gain some size.
In the mean time, start reading and looking at photos so you can decide your plants' future.
Baja_Costero said:Bonsai soil and cactus soil should be pretty close, I think. Some observations about the plants in question....
The Portulacaria is often grown to size in a large container and then cut and rooted for display in a much smaller one. So temper your ambition when you see pictures of gnarly fat old plants and imagine yours one day looking the same, without a few extra steps and a much bigger pot along the way. The best thing you can do at this point is provide the strongest light possible and watch how the plant grows, so you know what features you might want to preserve and amplify.
The Crassula is an interesting plant for miniature gardens and very highly branched plants can be nice as bonsai. It tends to grow strictly vertical (going sideways as it branches maybe but always shooting up at the end). So not the best subject for a sweeping sideways look. I would recommend waiting until your plants are twice their current size or more, and then you can consider taking cuttings to start new plants (removing the top third or half of each stem) and observe how the plant responds by branching. It is one of the easiest succulents there are for starting from cuttings, and it will reliably branch afterwards. As a bonus it does very well when planted with multiple stems in one pot as a sort of miniature forest.