Shanghai Trip Advice?

[chicagonoob]

I've been on the boards for a few months, having chimed in here and there on a small variety of topics. I also posted an intro thread a few months back...

http://www.rolexforums.com/showthread.php?t=435428

Back to the topic at hand.....I'm schedule for a work trip to Shanghai in early January. This will be my first visit to China and I was hoping to get some advice/have some basic questions answered. I'll be there for 4 nights, staying in a prominent international hotel in Downtown Shanghai. I may have a half day of "leisure" time, with the balance being on-site with our client. My company is relatively small, with limited experience on Chinese travel. Please bear with me if some of the questions seem elementary in nature!

Given the diversity and global nature of the TRF Community, I thought I'd throw a few of them out to the forum for some sage advice...many thanks in advance!

-Cell phone: I currently have an iPhone 6s on ATT. Any recommendations on best practices while there? Purchase a temporary plan from my current carrier, etc?
-Power adapters: Is it necessary for me to bring this?
-Taxi/Transport: Should I have car service arranged for airport transport, or is taxi ok? Same question for daily/nightly transport (dinners, etc).
-Airport: Any pluses/minuses to Pudong vs Hongqiao?
-Airline: Flying from Chicago, my options are American or United. For domestic travel I primarily use Southwest (love the Companion Pass), so no allegiance to either as far as rewards are concerned.
-Other?: Any other macro tips would be much appreciated!

Thanks again for your input!!