Question about Marabu Porcelain and glass painting pen Kids

Probably not. The packaging states that the pens are only suitable for glass and porcelain and that the surface must be free of dust and grease. To put it bluntly, paraffin is actually a solid oil. I assume that the paint will roll off it. At the latest, there will be certain problems with candles when they have to be baked at 160°C! :-) or :-(
I recommend candle paint, e.g. article 10078648 (but I have no experience with this).