Which platform allows us to find out more about the companies before we finance their loan? I.e all of their company's information, and their financial situation at the point of their loan?

I speak from personal experience with both Funding Societies and MoolahSense. Both of them give some basic information in fact sheets for each loan - so that perhaps answers the first part of your question.
As to the second part of your question - "all" information is not likely to happen. For example, Funding Societies does not reveal the name of the borrower (last I remember). Basic information about their financial situation at the point of the loan may be given, but if such information is revealed, it will usually be priced into the higher/lower interest rate. I suggest that, unless you are an insider or are somehow able to gain inside knowledge on how well the company is doing, if you do engage in the loans, it would be more useful to consider the frequency/percentage of defaults of each PORTAL, and the type/sector in the loans occur. In that way you can choose the portal correctly, and further adjust your preferences according to the type/sector of the loans.