No, they won't. Nobody will remember 10,000 emojis.

I used emojis for a while on phone texting. I eventually realized they were juvenile and stupid, and stopped.

Save the artwork for wonderful things like the illustrations in the Pooh books.

If you believe people who have no idea what they're saying, it's "慢".

I like yours though.

In the actual development of writing, it isn't likely that a picture of a snail would be used to represent a semantically related word. Even in the earliest systems, where you could use a picture of a snail to represent the word "snail", it would be limited to (a) the word "snail", or (b) some other word that was pronounced identically. This is how it worked in Egyptian, Akkadian, and Chinese.

For example, 慢 is the Mandarin word for "slow", and it's pronounced "màn". There is a logic to its appearance: the component on the left, 忄, represents that it is a mental state† (I'm not sure why this was felt to be true of "fast" and "slow", but it was), and the component on the right, 曼, just so happens to be pronounced "màn".

(Most sound indications in Chinese characters are no longer that exact. They used to match better, but many centuries of language change followed. 丁 is dīng; 打 is dǎ.)

† Some more typical characters in the same category: 情 "feeling" (n.), 怕 "fear" (v.), 懂 "understand" (v.), 恨 "hate" (v.).

Those darn Lombards! I'm going to stick it to them in this marginalia.