The answer to your question on allowable motors is yes which can be found in Rules 21 and 22. Note that the wording is "in any one match" and "everything you have with you in the competition area altogether, on and off the field".
[See the pictures in the rules via the link above]
22 - Quantity Limits - The quantity limits given above don’t just apply to what’s on your robot “right now.”
- The referee adds up everything you have with you in the competition area altogether, on and off the field.
- All of it counts toward your total for the current match.
Best of Luck. Have Fun!
Bill