This seems especially creepy reading it because I remember reading a guide on cults and typical patterns of behaviors found among members while researching for my story, and this is pretty spot-on with a lot of what the guide said. Make the target and the members feel bad for dissenting (in your case it was achieved with just being very nice but other groups use humiliation and ostracism), make then doubt their own judgement by confusing or berating them to make them feel they need your guidance, never reveal all the information to new recruits or to members in the cult that are outside the "inner circle" of leaders, and most of all make it difficult for them to escape your reach by setting yourselves up early as central and inescapable within their lives. Wow, it seems like you dodged a bullet there. I may be unimaginative, but I don't know how creepiness could be set up as the direct solution to a problem. I suppose the baron provides Elias with some of the information he sought out in contacting him and attempts to set himself up as a friend/romantic interest for Elias (who has been alone and very much depressed and lonely for some time), but I don't think of that so much as because Fran is creepy as because he has ulterior motives...that are screepy. I've only read one book by Kazuo Ishiguro, and I remember feeling the same sense of frustration and dread. It was great. Whenever I finish The Magus I'll check that out.
Many manipulators start out by helping and over helping people. They'll get the group to accept the newcomer by expressing how much this person needs his help, how they're at a bad time in their lives now, etc. Then the charismatic one helps more and more, until you don't want their help yet they're insisting on it. They show up at your kids' soccer practice with drinks and snacks for the whole team because they knew you'd be far too busy to be able to do it. They insist on giving you a ride home when you drop your car off for repair, then butt into your discussion with the mechanic until he's talking only to them. Then tell you how lucky that the mechanic agreed to lower the price by $10. They come to a cook out you're having and don't just bring a dish to pass as requested, but bring 5 or 6 dishes because they know how stressed you get when cooking for so many, even though you don't. You cancel plans because your child or you are sick and they cancel theirs as well, showing up at your house with soup, crackers, tylenol, whatever to help care for you or the child. They tell the group, your own friends and family, how grateful you are for their help because you needed it so much. By the time they've become so overly intrusive, you feel so indebted to them that it's hard to tell them to back off without feeling that you are ungrateful or selfish, etc. And yes, this is from personal experience. I've also seen many versions of this in different work environments over the years. It starts out slow then builds up over time. But I've always found this insistence on you needing them just to get through the day and their slow insinuation into your life to be very creepy.
