Am I right in assuming that an Attribute is formatted as “{attribute=value}”? Is there some other hidden value/signage as well that we do not see? Reason I ask is I want to fly in a long list with attribute-type values and don’t want to spend all day re-assigning those values by hand, when I can pre-format them.
Thanks!
Yes (with space separators, and some shortcuts for ID’s and classes)… if you are talking about Markdown file format. The syntax is taken from pandoc’s header attributes here: Pandoc - Pandoc User’s Guide.
This same format can also be used for custom inline attributes.
I’m not quite following. Hope the above helps, if not please ask me again! 
I know we can add/edit attributes via the Attributes panel (and some bundled ones like Flag, Priority, etc via a row’s context menu).
I wanted to confirm that adding attributes inline while typing is not supported? (ie derive them from the string of the row)
Yes, that’s correct.
I have a non-Bike .md file with dozens of entries, each of which contain tags that i would like to convert into attributes:
And so on. Rather than manually go in and edit each tag to format them into attributes, is there a way i can format them and then open the file in Bike?
At the broader level i am also wondering whether the attribute values themselves could, if needed, be edited outside of Bike in a markdown editor?
Yes, they should be fully editable outside of Bike.
Above when I said yes to “adding attributes inline while typing is not supported” I mean when editing in Bike editor. If you edit the attribute syntax outside of bike it should work and be picked up by Bike next time it reads in the attributes.
I would experiment. Save a Bike document as markdown. Add some attributes. See what they look like. Then try editing those attributes outside of Bike, and you should also see them in Bike when the file is next loaded.
Yes, you would need a script that parsed those attributes out and then used the above linked pandoc attribute formatting (at end of line) to add them back.
This is amaaaaazing 
I already tested the syntax within and outside Bike, creating/editing/confirming attributes. Everything is working silky smooth!
Additionally, the facility of assigning and editing attribute values (especially via keyboard) once within Bike is EXEMPLARY.
I am enjoying this SO much. Going to transfer over my enormous task file this weekend, beer by my side 