The best way to do this properly is to learn and evaluate as much as you can, and then hire a professional to guide you and instruct you. Although the questions you ask are legitimate and worthy, what they do is belie an almost complete lack of understanding of the immense learning
curve ahead. You ask if it is easy to drive twin engines. That is like asking if it's easy to drive a dual engine
aircraft and the answer is sure...once it's up in the air and as long as you don't have to land it. The boats you are looking at are so different in style, design and construction and capabilities, but how did you even come up with a short list already? Sure, it is wise to seek free advice online, but it's wiser to seek out a professional who can work with you on a personal basis and really help you determine your goals and needs.