Ball placement in Auto

Can the ball start in front but not in the robot during auto, or is it either in the robot or on the rings?

You should read up on Section 2.3 of the 2016 Game Manual:

Each MATCH begins with eighteen (18) BOULDERS in the ARENA. BOULDERS are staged before the MATCH in the following manner:
A. Six (6) BOULDERS are staged evenly along the length of the Midline, 3 ft. 9-1/2 in. apart as shown in Figure 2-35. Small rings are used to keep them in place prior to the start of a MATCH.
B. Three (3) BOULDERS are staged in each CASTLE
C. Three (3) BOULDERS per ALLIANCE are staged on or in each ROBOT or in the CASTLE.

Emphasis mine.

Section 2.3 lays this out.

Each MATCH begins with eighteen (18) BOULDERS in the ARENA. BOULDERS are staged before the
MATCH in the following manner:
A. Six (6) BOULDERS are staged evenly along the length of the Midline, 3 ft. 9-1/2 in. apart
as shown in Figure 2-35. Small rings are used to keep them in place prior to the start of a
MATCH.
B. Three (3) BOULDERS are staged in each CASTLE
C. Three (3) BOULDERS per ALLIANCE are staged on or in each ROBOT or in the CASTLE. See
Section 3 (3.2 MATCH Logistics) for more detail.

3.2 states:

When a DRIVE TEAM loads their ROBOT onto the FIELD for a MATCH they may elect to:
A. pre-load one (1) BOULDER in or on their ROBOT such that the BOULDER is fully
supported by their ROBOT, or
B. transfer their BOULDER to a HUMAN PLAYER in their CASTLE.

Must be supported by the robot, or on the rings.