I've had my HiHY for about 5 months. I live in the city and have a kid so the bigger hybrid option was a necessity. I've found out that unless I drive for 5 or more miles, or more than 10 minutes, the Hybrid converter doesn't warm up. Most of my trips are within town and the ICE is running 80% of the trip. Is there a way to get the Electric part of the engine to warm up faster? Is this what I keep hearing about the "break in"? It's pathetic because my speed and the terrain are all perfect to make my MPG closer to 30 and all I can get is 24.7 due to the short trips. Had I known this, I don't think I would have gotten the car . I wouldn't even care about the MPG cause it's still way better for city than any other V6 SUV, but I'm still polluting as much as the rest of the fleet unless I can get the EV aspect to kick in faster. Thoughts?

Don't worry about the rest of the fleet. What you have is stellar gas mileage for a V6 SUV. I think the closest vehicle to the Highlander is the 3.5L V6 Rav4 in terms of mpg. You still pollute 10-15% less that vehicle.
SUV's will never be as efficient & effective as a car which will never be as efficient & effective as a fully loaded schoolbus. Each vehicle has its ideal use. The SUV has more space & power than your typical sedan.
This SUV has more power and better mpg than the typical 5+ passenger SUV. Your choice to pick this V6 SUV over another V6 SUV will benefit the enviroment.
I'm sure that when Toyota brings over the 4cyl Hybrid Van from Japan (If they do), there will be a big shift of interest from the Highlander. Until then, if you really want to help the enviroment, you can downsize the vehicle or increase the occupancy (volunteer to do some carpooling).
The warming up process and breaking in has more to do with the ICE and fluids. Your MPG will improve as the ICE breaks in.

I'll say it again, your MPG is stellar for a V6 SUV.

has your ICE broken in? Does that really result in the converter warming up faster? Is it worthwhile to just sit and idle for a few minutes?
You wrote---
"The warming up process and breaking in has more to do with the ICE and fluids. Your MPG will improve as the ICE breaks in."

What fluids and what else can i do to speed the break in process?

This is not a true statement. The engine in the HiHy reduces emissions output even compared to a non-hybrid vehicle with the same MPG. So even though you are taking short trips and not getting the full advantage of the Hybrid, you are still putting out less pollution.

Let me separate the two and make it simple:

Breaking in: The engine wears with use. At some point, the friction is minimized and the engine runs at optimum. Just use the engine and allow it to break in normally. We're not race car mechanics, we'd have to waste alot of gas and oil to break in the engine sooner.

Fluids: The ICE is most efficient when at it's specified operating temp. The coolant and oil need to get to that temp.
The engine & transmission oil need to get to the moving parts to minimize friction. The engine oil is like flour impregnated butter, initially its thick and in one place, it warms up, gets all over and greases the works then the 'flour' thickens so as to not burn the butter. Forget about idling to warm up. Just accelerate with moderation until it warms up fully.

BTW the converter (catalytic) heats up in a matter of seconds. Its part of the exhaust and reduces harmful emissions.