I am unable to identify N.N. While the translation Advertisements from Parnassus is certainly by him, it is not even clear if the same man is responsible for the Secretaria di Apollo. Since, however, both works appear in the same year, and since the title page of the first promises but does not print the second, it is safe to assume that N.N. is the translator of both Works of Boccalini.
From Secretaria di Apollo or, Letters from Apollo (1704), I. 230-1 (Letter addressed 'To Spencer', originally to Petrarch):
The Advertisements which we daily receive in Parnassus, concerning the miserable condition of our beloved Poetry, encrease our desire to provide some Remedy against the Disorders it labours under; and for this end we formerly sent Homer and Virgil our faithful Servants, Embassadors to most of the Princes in the World, to perswade 'em to take Care in this Matter; but since those Endeavours have proved vain, we command you as the Prince of English Poetry, to declare our Intention; which is, that all those foolish Bards, who have never drunk the Waters of Aganippe, amongst our Muses, but only Muddy Ale in the Cellars amongst the drunken Rabble, may be made to understand that they merit the Punishment of perpetual Infamy, if they hereafter presume to defile Paper with Ink and filthy Grubstreet Rhimes…. You know, in former times the Subjects of Poetry, were only Heroical and glorious, great, virtuous and conspicuous Persons, whose Actions were renown'd all the World over; whereas the necessitous Bards of the present Age choose worthless and obscure Subjects; and what is still more ridiculous, whereas one Poet was formerly to celebrate many Heroes, now many Poets are not able to satisfie one ambitous Upstart who deserves a Satyr, not an Epick Poem in his Commendation….