Whatsoever is usually only at the end of a sentence, like “at all” “I have no interest in this whatsoever” which means “I have no interest in this at all” Howsoever I’ve never heard used before. In your two sentences it would be much better to just say whatever and however

It’s possible I’m wrong. English has so many weird phrasal verbs! I think you can spy out something but I don’t think you can spy someone out. So you could “Spy out his hiding place” but you can’t “spy him out” But again I may be wrong, just have never heard it used.