I don't feel particularly qualified to answer 1) or 2), but my guess is that the first is imminent, and the second will probably be within the next decade or so. The technology for detecting extrasolar planets has blossomed so unexpectedly in the last few years that it would take a real pessimist to imagine that it will not continue to progress explosively at least for the near future.

Life arose on earth almost as soon as it cooled off. This, coupled with the circumstantial evidence that single-celled life is probably inevitable in any environment even remotely capable of supporting it, and the ubiquity of those environments in nature, suggest that simple life is common throughout the universe and will be detectable by the environmental effects it will have on its host planet.

As for 3), I divide that into two separate questions:

3a) Multi-cellular life is something else; it arose very rather late (500My ago) in earth's biological history and it is not clear that it is an inevitable result of biological evolution. There remains a distinct possibility that multi-cellular biota may be much, much rarer than microbial life, and in any event, there would be no way of detecting it unambiguously at astronomical distances.

3b) Intelligent life followed soon on earth (geologically speaking) after the appearance of multi-cellular organisms, so if one dare make guesswork based on only one data point, it can be argued that it is much easier for multicellular life to evolve intelligence than it is for individual cells to clump together into multicellar creatures.

Of course, it is possible to conceive of intelligent colonies of single-celled microbes, and a thousand other variants of life-as-we-do-not-know-it which may be common througout the cosmos but which we cannot conceive of because we've never seen one, but there really is no point in speculating on possibilities about which we have absolutely no hint or evidence of. I'm not saying they're impossible, just that we can't say anything meaningful about them.

From what we can tell so far, suitable suns are common, planets are common, life will arise if given half a chance, intelligence is probably rare, and intelligence with the capability and desire to develop technologies detectable over interstellar distances is probably even rarer. That's a lot of uncertainties and sheer WAGs to plug into the Drake Equation, but I've done it, and my best-educated guess is that there are probably between a hundred and a thousand species technically capable of communcating with us in the Galaxy right now. During the lifetime of the Galaxy there have probably been between a thousand and a million species that fit that criterion. One hundred billion stars give us a lot of wriggle room, but even if they're out there, a very strong possibility exists that we may never know for sure