If you ask this question for me I'll definitely say that both are not preferable it is much better to buy moto G4plus or moto G5 which have good display, camera quality and amazing battery with quick charging
Lenovo Z2 Plus is a good phone and has Flagship like features in it.. and yes it is a better phone than Mi5 as both have the same processor, Both design statement , Similar level of camera, but Z2 Plus has better battery ,More RAM and has 64GB of Internal storage .. and all of these are at much lower price range..
Motorola Moto Z2 Play is costlier than Motorola Moto G5s Plus making a price difference of around 10k but There is not much difference in features they provide. Lets compare them in detail to decide to best one for you.
Slimmer: Motorola Moto Z2 Play has a thickness of 6mm which is 25% than 8mm thickness of Motorola Moto G5s Plus. Slimmer devices are easy to carry and look more fashionable.
Light Weight: Motorola Moto Z2 Play is 13% lighter than Motorola Moto G5s Plus. Light devices are easier to hold without tiring your arms.
Dual Camera: This is where Motorola Moto G5s Plus overtakes Motorola Moto Z2 Play. Motorola Moto G5s Plus has a dual camera which is useful in enhancing certain effects like blur, zoom and wide-angle photos.
Verdict: I recommend you to go for Motorola Moto G5s Plus because it is cheaper and also have a dual camera which is more useful feature.