The origins of Halloween are irrelevant to its present-day manifestation. To claim otherwise risks a Genetic Fallacy.
In Orthodoxy, we trust the words of holy elders and God-bearing bishops over others. I do not know who Fr. Benjamin Naasko is. I am sure he is a good man, but his opinion does not trump that of holy elders, who have been cited in this thread. Each person is entitled to their view, but that does not make their view valid.
Our Lord says that bad trees cannot bear good fruit. St. Paul tells the Ephesians to have no fellowship with darkness. We cannot hope to 'celebrate Halloween in a holy way' given the current cultural milieu, despite the feast's apparent origins in All Saints/Souls Day. Instead, let us reject any celebration of Halloween with love towards our neighbours.
Since you are a catechumen, I would advise you to seek the consensus of holy fathers when exploring this and other issues.