You can simply use PHP artisan command to create Laravel migration table. For that you will have to use this command:
php artisan make:migration createtodotable
Some times when you are creating table in Laravel with migration, you might get error. In this case, check you MySQL version on the server. It should be at least 5.7.
You can follow this guide to know how to force laravel https to redirect. You can basically use middleware class to enable it. Or you can do it through .htaccess file.
If you have created multiple database connection, you have to close the connection to one database and then connection to another database. You can follow this guide on Codeigniter multiple database connection to know how to do it.
You can also prevent php sql injection by making user's input to be authenticated for definite set of rules for syntax, type and length. You can also remove unused stored procedures to prevent it.
I think the most efficient way to handle sessions in php is using Redis server. Redis can be used for cache and for session handling as well. To configure your app to use redis for sessions, you have to edit your index.php file and add script in it. Apart from redis, memcached can also be used, but now redis is a more preferable choice.
Source: Redis as a PHP session handler.
Setting up cron jobs with cpanel is a time taking task. You have to specify all the scheduling manually and then execute the script manually. This is why I find Cloudways PHP site hosting platform better because it provides a simple UI where you can schedule the cron jobs easily and quickly.
Instead of PHPCI, I would recommend TravisCI. This is tool is great for PHP continuous integration because it is easy to use with your projects. Travis doesn't require you to install it. It is an online tool where you can login, connect your github repo and get started. Your github repo should be connected to your server and it must have travis.yaml file.
That's a nice tip. But first you have to integrate Elasticsearch in PHP. You can do that using Elasticsearch PHP API.
Manually setting up Debian server on Linode is not an easy task. Setting up a server on Linode and then configuring your application with the stack could take you a day or two. It is better to go with some Linode hosting PaaS where you can launch a Linode server without having to manually setup a stack.
For this your integration method should be safe. The safest method to for Laravel stripe integration is using Stripe API.