A Chinese competitor to Boeing?

1. Based on precedence, I do not believe that the C919 would become certified by the FAA anytime soon. COMAC's first aircraft, the ARJ-21 has yet to be certified by the FAA even though the aircraft has entered into commercial service. A shadow certification process has been undertaken by the FAA between 2010 and 2015 to assess the company. This lead many to believe that the FAA was intentionally hindering the process of certification because of economic and political reasons (Govindasamy & Miller, 2016).
If the company's first designed product has not been certified by the FAA, then I do not believe the C919 will be certified anytime soon. Maybe the FAA does not see COMAC as a viable company that will be able to maintain production of airworthy aircraft.
2. If the FAA does indeed certify the C919 and US carriers do order models of this aircraft, I see US carriers having difficulty in convincing the general public that these aircraft are safe. Even though most people do not have an idea of what aircraft they are traveling on, I see this becoming a media issue. I feel that the media will sensationalize the situation by insinuating that US carriers are operating subpar "Made in China" aircraft which might cause a public backlash.
As for finances, I feel that the current administration will not be very encouraging for US carriers to buy Chinese made aircraft. Because of added taxes, it may not be economically viable anymore for US carriers to buy a COMAC.
3. COMAC is a state owned limited liability company according to the company's website. Its mission is "to let China-made large aircraft fly in the blue sky". Currently, the manufacturer produces the ARJ-21 and is working on testing the C919 before it enters commercial service. There are no other aircraft in the works currently, although the company may design other aircraft later on ("Introduction" n.d).
4. No, I do not feel that other companies might enter the market as competitors to Boeing and Airbus if COMAC aircraft receive FAA certification. I feel that the long and tedious process for COMAC's FAA certification will discourage other manufacturers from pursuing the same thing. Not only that, the research and development of aircraft design is very costly. It will take a lot of money and investment for a company to start developing aircraft.
5. Although Boeing and Airbus have not directly responded to COMAC's C919. I think that the Airbus A320 NEO and the Boeing 737 MAX, which are both newer versions of the classic A320 and Boeing 737 series, serve as the main competition to the C919.

References

Govindasamy S. & Miller M. (2015). Exclusive: China-made Regional Jet Set for Delivery, but no        U.S Certification. Reuters. 
    Retrieved from:http://www.reuters.com/article/us-china-aircraft-arj21-exclusive-idUSKCN0SF2XN20151021

Introduction. COMAC.
   Retrieved from: http://english.comac.cc/aboutus/introduction/