Hello Sir/Madam,
Greetings!!
I have experience hosting website on AWS EC2 Linux Ubuntu hosting, I have experience installing PHP, Apache andy MySQL on EC2 with SSH. I will also point your domain to AWS EC2.
In your requirement you have mentioned to use AWS S3 for media but I have one question here. As you also mentioned that development is completed so does developer have did the coding to upload/get media from AWS S3? If yes then only it will be possible to host media to S3.
Apart from this if your website will have heavy traffic then we can use AWS RDS for MySQL.
Please consider me for this project and I will not let you down.
Thanks.