Hi there,
I have the skills you're looking for and I'm able to build a project from scratch, all by myself. Everything from design, to front-end development, back-end development to server administration; you can count on me!
It sounds like a long term projects and I hope the budget range is only for Phase 1 of the project. Integrations with Accounting softwares and so on will not be easy features. But if you're willing to make this a long-term business relationship, I can help you grow this product step by step.
The technology stack suggested is HTML, CSS, Javascript, jQuery, Bootstrap, PHP, MySQL and Symfony3.
The web application will run as SAAS, in cloud and will be built to be responsive and display properly on both desktop and mobile devices as best as possible in Phase 1.
Please lookup my profile and if you think we can work together, reach out and we'll talk more.
Thank you,
Cosmin