Faraaidh and Sunnats of ghusal

Repeating ghusal if any part of the body gets dry before washing another part of the body

Q: I have read somewhere that while making ghusal, if any part of our body gets dry before purifying the other part, I have to repeat my whole ghusal (i.e. suppose if the water output of the tap is too slow and after washing my head, when I reach to clean my legs, some parts of my head or arms had already dried, do I need to repeat the ghusal? 

Validity of ghusal after finding braces glue on one's teeth

Q: I recently got my braces off and there is still some glue from it stuck on my teeth. This is normal because the glue is transparent and may be difficult for the dentist to see. However, my next dentist appointment is next week and this week I will have to do ghusl after my haidh ends.

I can’t get an earlier appointment. When I looked online for solutions to get the glue off, they recommended stuff like baking soda but these things can damage the enamel. Will my ghusl be valid with this glue on my teeth?