Hey buddy, not a yank or working for Tainjin, but have flown extensively in the area and stayed in Tainjin many times.
1. Are there any U.S. pilots that currently work for this airline?
Not sure, but often hear yank accents on other chinese carriers, especially Spring airlines.
2. If so, could you please provide me with some info about work environment?
If you look at a few other theads on South asia you will see that there is a common theme, you don't get what you are promised, you are at the mercy of the Chinese with regard to pay and conditions, that is, once u jump through all the hoops that most of their own drivers could'nt get close to, then move 1/2 way around the world, it's too late to just turn around and say " see ya later " when they start shafting you. I have experienced the lies and BS 1st hand, it's not a myth. Even if they do pay what they promise, you will be fined for doing 11kts around a corner instead of 10, landing 40lbs overweight in a 160,000lb a/c, etc etc, so they will get you one way or another. Of course, unless you are a chain smoker your lungs wil be subject to poison pollution the likes of which must be seen to be believed, don't be sucked in by the photos taken on the handful of days per year when the pollution is actually less than 10 times the WHO standards, or 20 times on a bad day. The figures are wide and varied as with everything Chinese, but it is estimated over a million people die from pollution in China each year and the quality of life for 10s of millions of others is sub standard, and its not just in the air, they have destroyed the land and water as well.
From friends who work at other chinese carriers you have to put up with smoking in the cockpit, level 3 or worse english and absolutely nothing in common with the other crew member(s).
3. Also, the pay looks really nice, but I was would like to know how one's paycheck is taxed.
Tax is quite high, not sure exactly but around 35% average and China is not cheap to live in, unless you like a lot of rice ! Like most expats you will probably spend a fortune trying to get away from the place and good luck with staff travel, these people move around in multiples of 1000s at the numerous holidays throughout the year.
4. Also, how are the living arrangements in China and what would one expect to potentially pay for rent in China? How easily is one able to obtain a nice rental?
Pick a number : 400USD for a 35 sq mtr flat in a ****ty part of town or 3500USD for a 175sq mtr ( 1800sqft ) 3 bed 2 bath . If you like noise, living VERY close to millions of people, and having not enough room to swing a cat, then china is for you.
5. Is Parc the best company to go through to potentially obtain a job for Tianjin?
I believe PARC are very reputable, again you will see this if you research this forum
6. Any advantages or disadvantages?
Advantages ? better than unemployment. Disadvantages ? not much better than unemployment IMHO
7. Is there a way to prepare for any potential testing requirements to convert someone's FAA ATPL into the appropriate license for China?
Again, not personal experience but I believe the fail rate for the Chinese licence conversion is quite high, however I am sure there are plenty of " practice " exams available. The medical is slightly more difficult than NASA, which is hilarious when you see the average Chinese pilot who's only exercise is running to the smoking room during turn arounds ( thats the decent ones that don't smoke in th a/c )
Also they will give you a sim workout that would have 95% of their pilots crashing and burning, I think it's because they hate that they have to hire gweilos 
8. Any other info would be greatly appreciated!
If you have a family that have to go with you I would say Don't do it !!! If you are single, well hell, give it a go I guess, I just wish someone would have given me the above info before I left home, but hey, it's all right here on the net
Good luck !!