Clues
1.
Boris collected more treats than Selina and also collected more treats than the wizard, which was not Selina's choice of costume.
2.
Glen dressed up as a Ghost or a Werewolf and did not collect an even number of sweets.
3.
The witch collected fewer treats than Jessie but more than Selina.
4. Trish wore the pumpkin costume or witch costume and collected 6 fewer sweets than the child that wore the ghost costume.
5. The child wearing the pumpkin costume collected fewer treats than the child wearing the werewolf outfit.