Hello,
I am an excellent Web developer as well Server admin. I have more than 5 years of experience with all technologies . As you described in your job details, I am sure that I can do all. There are answers of your questions:
7) Question - Ubuntu / centos - which is best and why? - Both are fine, cs-cart is usually work well with centos.
8) How database migration from one DB to another DB can be done. will share 1 database.- You can provide me sql and I will upload that to server. Or you can share details for old server, I will migrate.
9) Various Health check services provided by amazon (where and how)- aws checks server with port 80 or 443 to review health and let you know if there is any breakage.
10) Link ip address with domain name- We can use aws route 53 for DNS and here we can use IP for website.
11) How to install SSL certificateSure, I will install SSL that you provide me from any SSL provider.
Looking forward to hear back from you.
Regards