This a- prefix was derived from Old English, a time when there was a lot more inflection (see also this source). Some of these words will seem old-fashioned (and some of them are actually obsolete), which is why it seems poetic.
Note that three of your words in the latter category are real English words (asail, abind, and adraw; adraw is obsolete).
In general, I think a lot of the time it would be understood, although it could be hard to parse (and therefore confusing) in spoken poetry in particular.
I am afoot
May be heard as:
I am a foot
To some extent, proper pausing, emphasis, and context help resolve this, but some people may still not understand what you mean.
Although they are real words, there are plenty of a-words that just don't sound right.
Earlier today (coincidentally), I discovered that "ahungry" is a word, although I've never heard it before. I'm a native speaker, but I wasn't convinced that it was a real word until I looked it up on the internet. Here's an example of ahungry in a poem. (I was just as skeptical, if not more so, about "anhungry", which appears to be an earlier, now-obsolete version of the word.)
It's hard to explain why words like "ahungry" don't sound right (it's my intuition as a native speaker); the only "objective" way I can think of would be look at recent usage (it helps to have good search skills).
It's important to note that verbs are different. You use the present participle of the verb, and a hyphenated "a-", like this: a-verbing. (In some cases, the hyphen may be a space, but it's easiest just to use a hyphen.)
Unlike some of the a-words in other parts of speech, verbs following this pattern almost always sound correct:
A well-known (and timely) example containing several other a-verbing constructs is The 12 Days of Christmas.