We ought to pump the brakes just a little on these signings, at least to the extent of not pencilling players into future lineups, even of the Marlies. The "TO" in ATO stands for "try out" and that's exactly what this is, a tryout. The Leafs brass will get to evaluate Lindgren and Engvall, at least in practice and maybe in games. This will give the two Swedes an opportunity, for their part, to impress the Leafs and maybe earn a spot next year. It is no guarantee of that, however.
Here is a news entry from a year ago:
http://www.marlies.ca/news/news.asp?story_id=3821
As you can see, the Leafs signed Witala, Marchment and Conacher to an ATO each. None of the three got an ELC, according to the Capfriendly list of the fifty Leaf contracts. All of them played for Orlando, with a cup of AHL coffee for one of them. I won't take the trouble to check back, but I am pretty sure that there have been a number of other ATO players who ended up with no contract whatever.
Getting an ATO is a step better for Engvall in particular than some had predicted. There was an article a couple of months ago in, I think, Pension Plan Puppets, that predicted we would never see Engvall on this side of the Atlantic. Clearly, this is one step beyond that estimate. But it's still a tryout!
As far as fan expectations go, the worst thing that happened to Lindgren was that pre draft comparison to Karlsson. It's set up some unrealistic expectations on the part of some enthusiastic fans. Fortunately for Lindgren, I doubt that management is affected by such comparisons.