That's right, to pay the commission, investors buy VSA tokens for fiat money or other cryptocurrencies.
1.5% charge from the commission is paid for the platform services.

Good news, dev! what Exchanges will be available?

You can understand how the system works on our WP.
https://vesa.io/VesaWhitePaper.pdf

What if 3 of 5 traders in my portfolio decide to buy Litecoin on 20% of their capital, for example. What will be my investments in Litecoin? 60%?

No, man, you counted wrong. 20% takes from their capital, not yours.
So, your investments in Litecoin will be depend on how much capital you trusted to these 3 traders

How many VSA can i buy on 1 EtH? What is the exchange rate?

Vesa analyzes all exchange users' transactions, generating the information on transaction
gains and losses, token value, balances, reports, etc. in real time. It lets traders and investors
objectively assess their achievement results.

Is it securely to give some kind of access to my capital?
It is very important question in "crypto-century", hackers are everywhere

Copycash has bad ratings on ico-lists, Copy trader is better than first one, and it is available to trade Forex on their platform, so it's good challenge for Vesa!
I believe that competition breeds goodness or at least commitment to it!

Hi, dev! Just try your alfa-version of platform, it's awesome!
Really like it, very easy to use!