Can a levy be placed on an account for a individual if the account is actually set up in a minor name with the individual being the guardian of the account or a UTMA account?

In my opinion, no. The guardian or conservator does not have ownership rights to the funds, so a levy in the name of the guardian or conservator (as an individual) doesn't reach the funds in the account.

...and if a levy is placed on a UTMA account in error, the custodian has 21 days to point out the discrepancy in ownership to the IRS (and the bank). He or she should do so vigorously.