Market Research for product development of Kids Craft Activity

My company specialise in supplying a sand art activity for Children which is used at school fundraising events, visitor attractions, and holiday parks. Children participate in this activity by filling up a transparent model with coloured sand, when they have completed their design they take it home as a keepsake.
We currently have a range of sand art bottle models, and i want to develop my product range to provide the most popular shapes that we don't currently have available.
Your research would find out what shapes/designs or characters would most likely sell the best, that we could add to our current product range. Probably narrow it down to the top 5

This is the key research I am looking for:

- Most popular Children’s characters in the UK at present (age group 5 to10). If available as secondary information ages 11 to 15. Age group 5 to 10 is the most important.

- UK kids trends for 2021, as chosen by kids

- Top 5 UK kids trends so far this year

- Facebook or other social media or parent forums or platforms (do a quick and simple questionnaire, or survey monkey questionnaire with link). Ask parents what is popular with their Children? What sand bottle models do they think their Children would like to see in future?
Note: may need to explain how this activity works in case parents are not familiar with the product. If we can find age of Children that relates to the parents comments that would be good.

Note: you could obtain some free desk research from sites like https://www.superawesome.com/ and other sites.

Finally you would give summary recommendations of sand bottle models we should prioritise to develop
Please advise how you would go about this research, especially if you think I have missed anything or there are other ways to obtain the information required