You can have multiple approval restrictions based on hirearchy in proposals, projects as well as finances. You can set approval permission to download a proposal or make the project flow in such a way that a senior person needs to approve the same before the final delivery.
We provide finance module to manage the income and expense of the company. We have an option for approval in CRM where you can give the approval for particular expense made and income earned in your company. Unless you do not provide approval for particular income it will be added as a pending income in finance and once you approve the same, it will be added as an income in your finance department.