Your points are all very valid. But I really want to stress the importance of giving the new brothers something to do. Don't assume that they will know what needs to be done, or that they are extroverts and will ask. I was blessed to join a Lodge where they had no problems giving me small parts to play on the degree teams, asking me to serve on the scholarship committee, and really making me feel not only wanted, but needed as well.
In every organization I've ever been involved with, there are people who complain that only a few people do all the work, from Church to Little League, and I always ask, what have you asked so and so to do? And just because you ask someone to do something that they can't or won't do doesn't mean there isn't a task that could be better suited for them that they would love to embrace. I promise, if my Lodge would have apporached me about cooking meals first (they didn't) then there might have been a totally different outcome. I don't cook. I don't like to do it, and people don't like to eat what I cook. It's a win win if you keep me out of the kitchen. But I love being on the degree teams, and I love doing the website, so you have to match the brother to the task, and don't give up. If you haven't have them turn down five assignments, you can probably still get them excited and active in some form or fashion.