Need advice on what to look out for in terms of Magento as a e-commerce platform

Dear forum experts,

I am new in Magento. Hence, I am hoping to get some feedback and advice on Magento from the experts here.

My boss is hoping to use Magento as a platform for e-commerce.

Reason being that it is an open-source and his staff can upload or change content easily without programming knowledge.

His objectives of this site would be to use it as a inventory management tool, besides the e-commerce transaction.

So, people can come and select the products they want and buy from there.

Secondly, the system is able to store the current inventory. When an order comes, the inventory module will display if it is low and needs replenishment and the store person can fill up the products per se and update the inventory list.

Hence, the store front must work seamlessly with the inventory system.

My question is : how does one search for an extension that meet the above needs?

I understand that there’s not an extension that can 100% meet the needs of a company’s internal requirements.
In this case, do we need to tweak the source code to achieve what we want? If we do so, what’s the consequences later on, if any?

Furthermore, is it better to out-sourced it out to a web-developer company or engage a person to do the job?

What are the important issues or pitfalls I need to be aware of to install such a system.

Thank you for your time.

I’d also appreciate it if someone can