Why coins are used tens or hundreds of addresses only for made two transactions, accept coins and send coins?
I don't know. Maybe this Block Explorer is wrong or is normal if you investigate coins block. I don't have skills and my knowledge of the subject is insufficient
then you have aggregation amount from prev transactions and split into 2 outputs.
Maybe because all operations is in chain blocks and after that you can keep track of every transaction. and this disruption can be there to ensure anonymity? I do not know but it just might be at these large amounts of premine.
Yes, information about premine have on your site, but open official site and try to find information about premine - it's not there, or it is written so that you can see it only if you know about premine and persistently searching this information.
This information should be more visible on page. Currently there are some error on page.