Our Standard Opportunity has a Master-Detail relationship our Custom Object, Hi-Level.  The Record Type on Hi-Level is used to change page layouts.  We can successfully get the Record Type to update via workflow when the field changes take place on Hi-Level, but are stumped when our criteria lies on the Opportunity.  When the Standard Field, ‘Stage’, on the Opportunity is changed from ‘Stage A’ to ‘Stage B’, we need the Record Type on Hi-Level to change from 'Private' to ‘Released’. 

Things I've attempted:

1) Created a formula field on Hi-Level that references the Stage field on the Opportunity, and created a workflow on Hi-Level to update Record Type  to 'Released' when the formula field equals 'Stage B'.  The formula field works perfectly, but it appears that workflows cannot update from formula fields.  Is that correct, or I'm a missing a key component?

2) Created a workflow on Hi-Level with a field update to mark a checkbox as True when Stage moves to 'Stage B'.  Cannot get the checkbox marked as True because its appears that Cross-Object workflows will not perform field updates from parent to child.  Am I enterpreting this correctly, or could I be missing something simple?

3) Attempted to created my second option using a workflow on the Opportunity instead of Hi-Level, but fields from Hi-Level are not available when I try to create a field update.

Is there any other way I can accomplish this without an Apex trigger?