Question 1: No! Why not just create the internal page and have it target the specific keyword? Your homepage is your brand, not a product/service page. Those are internal. They will rank for whatever you are targeting (if your SEO campaign is strong). Why are you worried about what your homepage ranks for?
Short answer: No. Make internal product/service pages targeting specific keywords and do not redirect your home page.
Question 2: Huh? Those two examples seemed exactly the same to me. Are you asking why some pages will show a sub directory and some pages will show the html page in the URL? If so, it's all in your structure. It doesn't really matter which way you wanna do it but having multiple directories may give you the opportunity to attach keyword targets such as "example.com/services/stuff-i-do.html" as opposed to "example.com/stuff-i-do.html"
The former example will bring the word "services" into your string.. IF you are trying to get your page to just read "example.com/services" then just create that directory and drop an index page in.
Hope this answers your questions or at least comes close.