To be dissolved (luomenōn). Present passive participle (genitive absolute with toutōn pantōn, these things all) of luō, either the futuristic present or the process of dissolution presented.
What manner of persons (potapous). Late qualitative interrogative pronoun for the older podapos as in Mat 8:27, accusative case with dei huparchein agreeing with humās (you). See 2Pe 1:8 for huparchō.
In all holy living and godliness (en hagiais anastrophais kai eusebeiais). “In holy behaviours and pieties” (Alford). Plural of neither word elsewhere in N.T., but a practical plural in pāsa anastrophē in 1Pe 1:15.