I  don’t know much about these two models, but it seems that they were produced from 1998 in the Kolarovo factory as a development of the  Stella model.  They had an Italian Morini engine - see the detail picture below. By this time this factory was trading as Mopeds Slovakia Ltd. as shown on the sales leaflet - left.
Below is an advert and news clipping from a UK trade magazine showing that they were attempting to sell these in the UK.  The pictures from eBay show that at least one was sold here.

I’ve discovered these pictures from Slovakia of a couple more of the Steward version, so they must have made a few. It seems that the Steward was designated model 143.

Technical Data
MS Steward type 143.001

This black Steward was up for sale on ebay in the UK.  It has a Puch engine fitted Instead of the Morini engine seen in all the other pictures on this page.  Perhaps some of these were supplied with the Puch Maxi engines from the Manet Korado which was being produced at the same time in the Povazska Bystrica factory? Or possibly a previous owner has changed the original engine?