Alice Margatroid and Marisa Kirisame are both magicians. However, only Marisa is human. Marisa is probably the odd one out here since most beings who use magic aren't humans. Some humans abandon their humanity when they become magicians, but it's unclear whether Alice followed this path. The Gensokyo Chronicle states that she used to be human, but it isn't always the most reliable source.
Alice's house is situated within the Forest of Magic. In addition to the usual rooms, it probably features a workshop where she conducts her magical research and a room for guests since she has been known to happily let people who get lost in the forest stay the night. The area around her home is also called the Forest of Dolls. This could be because Alice's dolls are often seen around there... or because straw dolls have been nailed to some of the trees.
Seeing visions is one of Alice's abilities, but how she does this isn't exactly clear. Perhaps she has some kind of magical eye. While both are revelatory sensory experiences, visions differ from dreams in that they only occur when you're awake. Depending on the type of vision, one can see the future, the past, things that cannot usually be seen, or even other worlds or possibilities. The ability to see tiny things as though through a microscope, seeing through other perspectives, seeing things far away as though through a telescope, and seeing through objects (think x-ray vision) can also be described as types of visions.
But what visions does Alice see? One look was all it took for Alice to discern that Fujiwara no Mokou wasn't alive. Was that thanks to a vision?
Suika has called Alice a magical creature before. When she did this, she emphasized how she herself was different from Alice, even though some would argue (particularly those who follow Buddhist teachings) that oni are also beings of magic. Magical creature is a relatively loose term that can refer to beings that need magic to survive, such as non-human magicians, demons, and devils. However, it can also be used to mean a being from Makai, though "Makaijin" is usually the term used for this. Is that what Suika meant? Did Alice used to be a human living in Makai?
"Slow and steady... Good, she hasn't noticed. *nom nom*... Hmm, when did Alice get so good at baking cookies? Does she practice cooking? Or did she use her magic somehow? So mysterious. I guess the only way to find out is to have another.... *nom nom* Hmm, now I want some tea. I think I can reach the pot if I stretch a little further...!"
"Why don't you stop trying to be sneaky and come in through the front door like a normal person?"