One oldish fart's breakdown, for discussion from the CCC definition:
an act or omission, in or outside Canada,
Check
(i) that is committed
(A) in whole or in part for a political, religious or ideological purpose, objective or cause
At least one statement suggesting this - check
(B) in whole or in part with the intention of intimidating the public, or a segment of the public, with regard to its security, including its economic security, or compelling a person, a government or a domestic or an international organization to do or to refrain from doing any act, whether the public or the person, government or organization is inside or outside Canada,
Good case to be made for intimidation - check.
and (ii) that intentionally
(A) causes death or serious bodily harm to a person by the use of violence,
Not THIS time, but note the word "intentionally" - I'm not a lawyer, but I read that as needing intent to kill/hurt (1st degree murder vs. manslaughter sort of distinction). I'm thinking a lawyer can point to the fact that it was late at night and (I'm
guessing) recce'ed to minimize chances of collateral damage. This would likely be the biggest wedge the defense could drive into the terrorism case - watch for it when these folks face the music in the courts.
(B) endangers a person’s life,
There's a case to be made others were endangered in the building, but same as above - intent needed.
(C) causes a serious risk to the health or safety of the public or any segment of the public,
Same as above - intent needed.
(D) causes substantial property damage, whether to public or private property, if causing such damage is likely to result in the conduct or harm referred to in any of clauses (A) to (C)
Intent to damage looks like it can be proven (given the statement and others like it out there), but given the hour of the attack, and if a recce was done, how "likely" is it that there would be death or injury?
or (E) causes serious interference with or serious disruption of an essential service, facility or system, whether public or private, other than as a result of advocacy, protest, dissent or stoppage of work that is not intended to result in the conduct or harm referred to in any of clauses (A) to (C),
Multiple banks being put out of commission by a hack? Maybe. One branch closed? Hard to make a case for "serious interference (or) disruption of an essential service, facility or system".
That said, if you can't legally pin "terrorist" on them, I'm OK with high-end sentence for
arson:
Arson — damage to property
434. Every person who intentionally or recklessly causes damage by fire or explosion to property that is not wholly owned by that person is guilty of an indictable offence and liable to imprisonment for a term not exceeding fourteen years.
R.S., 1985, c. C-46, s. 434; 1990, c. 15, s. 1.
Hell, if you want to be a stickler, what about any jerry cans of gas found in ANY accomplice's car, van or garage?

Possession of incendiary material
436.1 Every person who possesses any incendiary material, incendiary device or explosive substance for the purpose of committing an offence under any of sections 433 to 436 is guilty of an indictable offence and liable to imprisonment for a term not exceeding five years.
1990, c. 15, s. 1.