Yes, mixtures of this type are possible, and it's quite common with certain words. For example, 石鹸 has a rather difficult second kanji, and the word is often written 石けん instead. 轟音 is often written ごう音. And so on.
In your example, none of the characters is particularly rare and all of them are on the 常用漢字表 (the official jōyō kanji chart), so prescriptively speaking 魅力的 is probably the official or proper way to write it. If you don't know how to write it and you're doing formal writing, I suggest looking it up on your phone or other device and copying the kanji.
But that doesn't mean people never make this sort of substitution. In fact, they do it for all sorts of reasons! Here are the reasons I've come across so far:
- Because the kanji or its reading isn't on the jōyō chart (for example: writing 隕石 as いん石)
- Because the writer couldn't remember how to write a character, or didn't want to write out the entire character (sometimes 略字 are used instead with certain characters)
- Because the writer thought a character was too difficult for the target audience / age group (for example, writing 一生懸命 as 一生けん命 even though 懸 is a jōyō kanji)
- Because the character is missing from a font or would be too hard to read in a tiny or pixelated font (for example in old video games with limited fonts or display sizes), or because it's too hard to write a complex character in a very small space
- Because the writer believes a character has connotations they want to avoid (for example, writing 子供 as 子ども)
So although I think all of your examples are technically possible, most of them aren't especially likely. I think your reasons for writing み力的 are perfectly understandable, but I'm not sure why anyone would write something like 魅りょく的. (Still, you can find a few people on the internet who have written it that way, so I can't say no one ever would!)
By the way, some people find mixed kana-kanji words like this aesthetically displeasing. You can always avoid this problem by looking up the proper kanji with your phone or such, or writing the word in all kana if you prefer. (If you're doing formal writing, I would look up the kanji.)