Typically ADR hearings are beneficial only to cases where refusals are about suspected "non-genuine" relationships and the sponsor can provide additional proofs supporting the relationship. At an ADR hearing there is a mediator, the appellant, and counsel for the Minister of CIC. Minister's counsel runs the show and the appellant must convince them that the refusal should be overturned. That's not easy to do when the applicant was refused because of being criminally inadmissible to Canada.
At a full appeal hearing there is a better chance because it's a more "traditional" scenario where Minister's counsel presents their case, your lawyer presents yours and a Judge decides. But basically, when a refusal is about an inadmissibility they usually aren't inclined to allow the appeal, even on Humanitarian and Compassionate grounds. Not knowing what exactly was wrong with your husband's Malaysian police clearance, it's hard to speculate what might happen or what might be needed in order for you to win your appeal. If your husband was actually convicted of a crime, he most likely will need to wait until he can apply for rehabilitated status before he will be eligible to immigrate. They are not really inclined to let people with criminal convictions into the country. But humanitarian and compassionate consideration can apply when there are extenuating circumstances that surround the conviction, or when there are children involved, or when it's been a very, very long time since the conviction. Again, lacking details it's very difficult to give you any idea of what you might anticipate . . . but I doubt very much that you'll get anywhere in an ADR. Probably will need to wait for a full hearing and hope for the best.