Ivy & Cacti Help Needed

Ivy & Cacti Help Needed

Hello everyone! I am really happy that I have found this place. While most of my family (particularly the males) have real green thumbs, I don't take after them in that sense. All the same, I love cacti and ivy, and have some plants in my room. Here are the problems and questions: 1. I have what they call a "winter cacti garden" and one of the cacti is the common one you get for kids: the stalk is three sided and then it has a big, bright red fruit at the top. I have followed the instructions to keep it warm and in bright light and to water it when the soil is dry. However, this cactus's stalk has turned leathery and thin. Does anyone know what happened to it or what I could do to restore it? 2. The other problem I have with this little "garden" is another cactus: it has little segments that are supposed to be attached to one another it seems, yet some have fallen off and look like they were never attached at all, even though they grew from the main cactus. It doesn't look like it's rotting or anything, but I don't know. Anyone has any idea of what is going on? 3. I have this really small potted ivy that my cats like to munch on and I have been unable to stop them from doing so. It's survived, so I am not too worried about that. However, I have noticed that the main branch of it, at the base a little below the soil, has turned yellow and rotten looking. Have I possibly over watered it? It is growing some new leaves, so it seems okay, but I am still not sure. Advice of what I should do? 4. Last question, I promise. I have this small seven or more year old cactus that is leaning really far over to one side of its pot. What is the best way to repot a cactus without burying it too deep or causing more problems? I repotted it once before to a larger pot, but I didn't seem to have done a very good job of packing the soil properly. If you guys would like pictures, I would be more than happy to provide them, especially if they help you guys. Thank you so much in advance!
The Room in the East

The Room in the East

Mass ID

Mass ID

cantaloupes and tigger melons

cantaloupes and tigger melons

Can someone tell me what flower this is?

Can someone tell me what flower this is?

Update on my progress

Update on my progress

First post

First post