8 - "The video must necessarily include students reciting and gesturing, or may be there other solutions, such as voice-over, music, dance, slides, etc."
Although it is open to creativity, the video of the poem must show at least some student doing international gestures because otherwise the students from other countries will have only his voice in a particular language, that they may not know.
Yet, if the teacher considers interesting to do (besides this video with students gesturing) an additional audio-visual production in relation to the poem, you can make both jobs.The site will be able to offer both options (but there will be always a video with students reciting the text in their own language while they or other colleagues make the gestures.)
For the audiovisual production (an example would be a song with slides, but it can vary), the alternative to the gestures are the signs:
In post-production (at least with Windows Movie Maker) is not difficult to put signs like subtitles using the YoGoTe character fonts. Again, if this is too complicated, we offer ourselves to make this postproduction, but for that we must receive the audiovisual mounting not only the link to the video on Youtube.