What can I do for these cactuses? What kind are they?

They were given to me by a friend that decided they didn’t want them and had no idea what to do with them. The grafted one is more proportional then it looks in the picture, but it has a faint dry line on the bottom and the round one also has a very faint line. 

Is there anything I can do for this? What caused it? If I need to cut the grafted one then should I let it dry out more first? I would like to move them into a small pot together that won’t get dirt all over my window, but I am worried about moving them now. The dirt is compacted and rock hard but I’m not sure about if I should try breaking it up. Or watering them more. Do cacti like their soil like that? I have just been using a spray bottle to sprits the top layer of soil the fifth day I had them but haven’t watered it sense. The flesh is pretty soft so I thought they were okay. They came from a Walmart and I have them in constant indirect sunlight with 1-3 hours of direct sunlight a day. I’m assuming that is okay for them. I don’t plan to have them outside if they live. 

Can I remove the glued on pink flower? Is it worse to leave it or remove it.