Visitor Visa rejected. Advices for the second try...

[jp70]

I have a long term (girl)friend in Uganda. We are planning to start dating+meet first time in the UK. We tried to apply ourselves, but there was missing documents etc. so rejected. Is this affecting negatively to our second application? One problem is, that we do not have good 6 months bank statement history in a way that there is constant salary every month. For example I just started self employment , and just now getting more money. Also she gets money by cash from her shop where she works. And she has not even put it every month into her account.
So using our bank statements might not work.

My money situation is not very good regarding to my work-salary. But... I did get a business loan last February, £5000. I still have like £3000 left of that. Can I use that to convince them that I have money to pay all the tickets and pay her 2 weeks stay in London? How should I prove that its my money and I can use it for that purpose (I can of course in reality, but how to prove it)? Just to put that money on my bank account is not enough, I guess? If I have £2000 cash, how can I prove Visa officers that I can use it provide for her? Could the bank loan agreement paper be enough?

And if I have a way to prove that I can pay all, does she also need to provide her bank statements even though we are not using her money? Maybe just in case to do both...

The other thing I was thinking, that is it possible to use my brothers bank accounts and money to prove that he can pay my friends trip. So if my brother (who does not know her) provides a letter stating that he pays everything plus shows his bank statements for last 6 months, is that ok? My brother is rich and has well paid job. He also owns a house, so his money situation is definitely excellent.

Second main issue would be to prove that she can stay in my house (well, if they believe that I have £3000 cash, then they should believe I can book a hotel room?). I have a shared house, where 4 people lives. But we have a free big living room. Can I use that as a place for her to stay? I guess I have to ask landlord to provide a letter proving this room exists.

Thank you.