I think to tack against the wind on the schooner you'd have to draw the square sail and rely on the jibs and lanteen, mainly because on the playmobil ships the shrouds get in the way of the square sail being able to pivot much more than a few degrees, and the square sails cannot be tacked. Regardless of being able to use the square sail or not, to tack against the wind we need a true keel, long and true. You cannot sail close hauled without a keel to negate lateral forces and redirect them in the ship's forward direction. Otherwise the playmobil ship is nothing more than a bowl floating aimlessly in the water.
As far as getting her back, in either case, even with a motor, I would attach a line to her stern (up high so as not to be entangled with the propeller, if you have a motor installed) so you can pull her back if she gets too far away. My other idea on this would be to let her sail free, but use a remote control tug to taxi her back to shore if you have to. Or eliminate the tug altogether and install props to act in a tug's stead.
I see no shame in adding a motor for backup purposes; even modern tallship replicas like the Lady Washington have motors for taxying and when the wind is not ideal. I do know, however, that the Lady Washington relys on the wind majority of the time, which can carry them at times even faster than their on-board engine at full speed.