No, you can select any depository, but there are depositories that Digital Trust currently holds metals with.
Segregated storage is when you choose to store your Precious Metals in a separate vault at the depository storing your metals. There are typically higher fees associated with this storage option. Non-segregated (commingled) storage is when you choose to store your metals in a vault that also holds metals for other customers. Commingled vaults have sub-accounting in place for each customer to ensure appropriate accounting.
No. You can only contribute cash to your qualified account with annual contributions or through rollovers or transfers from other qualified accounts.