With the vowels ommitted, is there potential for ambiguity?
SD
Only if you don't know how the words are supposed to be pronounced. nd vn thn, mst wrds wldnt b dffclt t fgr t.
Now, if you are a native Greek speaker, and you are trying to translate the Hebrew scriptures into Greek, and you don't consult with someone who actually knows what potentially ambiguous words mean in context, then sure, you might run into trouble.
Very little. The Bible, children's books and poetry are typically printed with vowels, though vowels are not part of the Hebrew alphabet; if you've seen Hebrew, the vowels are little dots and lines mostly under the letters. A normal Hebrew book for adults might have one or two vowels put in where there would be ambiguity without them. Magazines -- at least the ones I've seen -- don't bother.
When the Greeks adopted the alphabet from the Phoenicians, they found that Greek needed written vowels and used letters that Greek had no corresponding sound for as the vowels they needed.