Uhhhh so after putting way too much thought into it and scrutinizing in-game N's Room to look at apparent toy sizes and consulting Kratos' and Keldeo's personal reffing scales (the only ones I know of that mention specific sizes for Minimize), I'm going to say it makes sense to me that it probably could after two Minimizes, but with just one it probably wouldn't be small enough.
(Litwick is about a foot tall, and these toys look to be mostly building blocks plus a basketball and a train set, so Litwick would probably have to get down into the three-to-five inch range or smaller to squeeze in between the cracks, which seems to be approximately more consistent with two Minimizes than one based on Kratos' scale, at least, and would require more like three Minimizes on Keldeo's scale but that seems excessive to me.)
(Litwick is about a foot tall, and these toys look to be mostly building blocks plus a basketball and a train set, so Litwick would probably have to get down into the three-to-five inch range or smaller to squeeze in between the cracks, which seems to be approximately more consistent with two Minimizes than one based on Kratos' scale, at least, and would require more like three Minimizes on Keldeo's scale but that seems excessive to me.)