Wumpo – Frostpeak Sentinel

Can a Pal's 【Strike】 become 0 or less due to the 【CONT】 ability of BP01-033《Wumpo – Frostpeak Sentinel》?

Yes, it can. If damage is to be dealt to a player while 【Strike】 is 0 or less, that damage is not dealt.

I have a copy of BP01-033 《Wumpo – Frostpeak Sentinel》 in the rest state in my base. It is put into the graveyard due to an attack from an opponent's Pal with 〈【AUTO】 Breakthrough (When the opposing combat Pal is put into the graveyard during this card's attack, deal damage to the opponent player)〉. The 【Strike】 of the Pal with 〈Breakthrough〉 was reduced by 1 due to the 【CONT】 ability of 《Wumpo – Frostpeak Sentinel》, making it 2 instead of 3. In this case, is the damage dealt by Breakthrough 2 or 3?

It becomes 2.