What composition of the information system do you recommend choosing?

Question

CMS

Mini-brief:
Business will be established as follows. The client enters the site, selects the necessary product and / or service, pays for it directly on the site. Information about the new order is transmitted to the information system of the head office, then the information is transmitted to the company's representative in the region. A representative of the company provides a product and / or service to the buyer, receives a remuneration - a percentage of the cost of the product and / or service. All accounting of information, financial and material flows is kept in the IS of the head office, if necessary, part of the information is transferred to another IS of the representative. The main warehouse of goods is physically one, from which goods are shipped to the warehouses of representatives in other regions. All sales go only through the site, the site has a regional binding, adaptive, SSL certificate. Goods up to 2000 items. Services up to 50 items.
IS - information system
IPS - information subsystem
Approximate composition of IS (you can offer your schemes):
1. IPS - CMS site
2. IPS - payment system
3. IPS - CRM customer relationship
4. IPS - ERP enterprise management
5. IPS - WMS warehouse management (third-party)
It is advisable to exclude from your schemes initially redundant in terms of functionality and expensive products of Oracle, IBM, SAP and others designed for large businesses. It must be understood that solutions should be offered for the small business segment.
One of the best options is the selection of IS components that interact with each other and minimal refinement / development at the site level.

Answer 1

You have painted well what you want now (better than: "it's like those, only ...").
But in order to give a sane answer about the technology stack, you need to find the performer and explain everything to him in more detail, since the devil is in the details. For example:

if necessary, part of the information is transferred to another IS of the representative.

Answer 2

www.ultimaecommerceerp.com

Answer 3

As this IP, you can use the 1C: Enterprise platform. It connects with the site through web services (client or server). In order not to install 1C on all computers, you can use web access.
Pros: There are a lot of 1C programmers, it will be cheaper than writing in php.
Cons: you need a license or a pirate.

Answer 4

Another option habrahabr.ru/post/245329