It's hard to tell. The idea that Lampard will sign soon is very believable. The idea that he will go to Melbourne has been mooted. Technically in the A-League you can only have one "guest player" (a 10-game signing entirely outside of the cap) per season and loan rules are virtually non-existent, and while this was originally assumed to be Villa people have commented that actually there has been conspicuously no mention of the actual contract status of Villa in Melbourne. As a result, people are starting to conclude that City have somehow found a way to persuade the A-League to let them have more than one short-term signing. Given this increasing belief, the idea of Lampard going to the A-League for half a season is more believable now than I would've given it credit for three months ago.
At the end of the day, though, I am always a strong believer in the notion that nothing is 100% certain until the club confirms it, so I guess time will have to tell.