Is it permissible to place a lantern in front of those praying in the mosque, and did the Prophet (peace be upon him) forbid that?

It is disliked for a worshipper to face fire in their Qiblah, because this resembles the fire-worshippers, according to many jurists. The Malikis and Hanbalis explicitly stated the dislike of facing fire, even if it is a lamp or a lit candle. However, the Hanafis held that there is no dislike in facing these things, because the Magians worship embers, not lit fire, and praying towards an oven (tannur) or brazier (kanun) that contains embers is what is disliked by them. The issue is a matter of scholarly disagreement, and it is better not to place a lantern in the direction of the worshippers to avoid the difference of opinion.