Speech Bubbles meaning

I am developing a toon story to illustrate my company's offerings. May be I'll use a landing page, or just create it on the home page.

I have 3 actors in it, a cab driver, a bpo company owner and me. I am using speech bubbles to connect the problem of cab driver's, bpo company owners to a solution that my actor will speak.

I am using rounded rectangle bubbles for all. Is that ok ? Do the speech bubbles have some specific meaning ? I know rounded direction means thought, straight line direction means talking. I tried to google, I just got a lot of text trying to explain, but no clear guidelines on what type of speech bubble to use when.

Edited, I wonder if I have represented the bubbles correctly ?