The tribunal said in each of the cases that Smith had failed to provide any explanation or justification for the lapses.
He was found to have made several breaches of the code of conduct. Further submissions will be heard before a decision is made on penalty.
Possible penalties include a fine, loss of licence, and award of compensation.
Immigration advisor Alungamonu (Laki) Tangilanu (Monu) was sanctioned for cases in which she was found to have breached the code of conduct.
In both cases Tangilanu failed to properly complete applications or file them promptly.
She had "not taken responsibility for her indefensible behaviour across a large number of complaints", the tribunal said.
She was censured, ordered to refund fees and repay penalties.
The tribunal had previously cancelled Ms Tangilanu's licence and ordered that she could not reapply for two years, the maximum penalty.
To reapply for a licence, she would have to requalify, and be considered fit to hold a licence. "Ms Tangilanu is on any realistic view permanently excluded from the profession," the tribunal said.
Sanctions were also imposed against two other advisors, Alyssa Lopez Tan and Yijun (Alex) Hu for breaches of the code of conduct.
Both were censured and ordered to pay refunds and penalties. Ms Tan's licence had already been cancelled following a previous complaint.