

Travelling Macau -> Jiangsu, Shanghai -> Italy
Hi,
I am an Italian national, staying in China for the whole second half of December. Among my travels, I will fly from Macau to Nanjing on December 29. Unfortunately, I realized my Chinese visa has only 1 entry validity, and I will have already used it by December 14, as I first enter China in SH. I will need to stay in Jiangsu (Taizhou) for the period December 29, 2018 - January 2, 2019. On the final day, I have tickets to leave from SH to Italy (Rome).
My questions are as follows:
1. Can I use the 144 visa-free policy, as I do Macau -> Nanjing (airport), Taizhou (Jiangsu), SH -> Italy, and stay in Mainland China only on December 29,30,31 and January 1,2?
2. Should I just tell my airline carrier (Air China) at the check-in desk in Macau, or do I need further preparation in advance?
3. Do I actually need to obtain my actual seats confirmed by Alitalia for the January 2 flight in advance? Usually seats are assigned only around departure. In my case so far, I only have purchased the confirmation of my flight, so I have my booking, but it does not report the specific flight seat I will have on January 2.
4. Do I need to register with a police department in Taizhou, where I will stay inbetween flights for the 5 days?
Thank you in advance for all your help!