Laravel PHP & SQL database CLI tool for Windows, Linux & Mac

How much would be the ongoing monthly development cost of a Laravel-based command-line-application which works heavily and directly with all SQL databases (including MySQL, Postgres, SQLite & MSSQL). The application mainly revolves around analysing & manipulating database schema and data. I would like a 3 person senior development team who have 4-5 years experience with: - Writing automated database tests with PHPUnit across MySQL, Postgres, SQLite & MSSQL databases - Fixing defects & writing new features in both the latest PHP 7.x code, as well as ensuring the code is backwards PHP compatible to PHP 5.x - Using continuous integration (CI) tools like Travis CI - Using virtualization tools like Docker - A high international standard of written English to write and update technical documentation in Markdown format - Experience developing command line applications & tooling tools for Windows, Mac and Linux - Experience in tuning databases for maximum performance - Expert level of usage with Git version control & experience with a rebase branching & merging strategy