What's the most useful ship and upgrades I can do with 19 points for rebel. I know I am very limited on what I could do. A wing or z95. I could also drop shield upgrade and get 4 more points and do a 22 point b wing and then that would leave 1 point that I have no idea what I could do with. But I will do that if a b wing is that much better.

I think the first question is: What's the other 81 points of the squad?

There's a few options for what you could do with the leftover points, but of course it's more a case of what works best with the ships you're already running.

It would help to know what the rest of your squadron is.

You mention shield upgrades which are almost universally not used, since there are many far better options for the modification slot. Dropping the shield would probably be a good idea right off the bat, but depending on which ship pilot it was on, you may want to replace it with something.

To answer your question, I'd say Prototype Pilot with Chardaan Refit for 15 points, and then you have 4 points to play around with. I prefer them to Bandits and Talas simply because of the manoeuvring options.

The rest of your squad matters but I can't think of a single rebel ship id rather have a shield upgrade on so cut shield upgrade and enjoy your 1 point initiative bid.