Folks, after going through the St Lucie inlet 3 times now, I'd like to report back and share my experience with you.
1) The inlet is well marked with temporary markers that the US Coast Guard constantly adjusts; As other said, don't follow your instruments, follow the markers and you should be OK.
2) I passed through high and low tide; At low tide the lowest depth
I observed was 7ft.
3) The biggest danger
I encountered was recreational power boats of all sizes going absolutely crazy. Total disrespect for speed limits, road manners and anything else you could think of. It is a zoo!
4) The current plays a significant role, I was getting 2knots, and I know it can get even worse.
5) A big portion of the seawall on the north side collapsed, which creates a very weird current right at the entrance of the inlet. The water
there rotates counter clockwise on the ebb tide. My suggestion is stay in the middle of the channel.
Thank you again for all the replies and I hope this info helps others.