For the first problem, I don't think that's possible, aliases can't switch the search location. AFAIK, this will be a feature in farr v2 (aka mercury runner).
Your second "problem", isn't really a problem, it's more of a feature, farr is designed to act like that. When you press a number, farr is supposed to launch that number's corresponding result.
Just disable the checkbox that i have signed in the attached screenshot, and your problem is solved
BTW, even with that checkbox unchecked, you can still launch results by pressing f# (eg. for the second result, press the key "f2")
Another way, if you want to keep that feature on, is to instead of typing the number (#), type '\' followed by the number (i.e. '\2', to type a literal '2').
Hope I've helped
 i forgot the screenshot