The SKU SDIN7DP2-4G is an eMMC 4.51, so you will need to refer to the JEDEC spec JESD84-B451 for all information not described in the Scandisk's user manual.
The Data-0 has no internal pull-ups into the device.
Data 1-7 have internal pull-ups, which are disconnected after power-up for the active lines, when a specific transfer mode is selected.
In the case of 4-bit mode, only the active signals are disconnected from the internal pull-up.
As Data0 is the only data-line at start-up which is active, it has no pull-up.
It will remain active during any transfer mode selected.
This information can be checked in the JEDEC spec, Chapter 5.3, Device Overview.
As the Data-pins are bidirectional and basically have open-drain buffers, external pull-ups are required on DAT 0-7 regardless of whether they have internal pull-ups or not.
This is required so that the bus is not left floating during non-active phases.
The guidelines for the external pull-up are still in the JEDEC spec (Paragraph 10.3.4, Bus signal line load).