In terms of themes you would need to have a design in mind then just go through the big ones.
Personally I’m a huge fan of certain authors and themes (have a look at Tom Rhodes and Foundry theme or one of his other files) and anyone with visual composer is going to be able to give you a good headstart - again you will of course need to style the CSS etc to look right.
Depending on the little bits and pieces of functionality you may be able to save time by using specific themes.
The splash page is not a slider but again any half decent developer could create that for you.
You can also look on www.studio.envato.com for vetted freelancers to help you out