3 points about nāmāparādha

Vaiṣṇava: It is said in Caitanya-Caritāmrta [Adi 8. 29-31]  "Gaur-Nitāi don’t take offenses"

hena kṛṣṇa-nāma yadi laya bahu-bāra

tabu yadi prema nahe, nahe aśrudhāra

tabe jāni, aparādha tāhāte pracura

kṛṣṇa-nāma-bija tāhe nā kare ankura

caitanya-nityānande nāhi esaba vicāra

nāma laite prema dena, vahe aśrudhāra

"If one takes [chants] that divine name of Kṛṣṇa many times but still there is no prema, and no stream of tears, then I know there is a lot of aparādha and the seed of kṛṣṇa-nāma does not sprout there. There is none of this consideration in Caitanya and Nityānanda. If you take their names tears will stream."

Advaitadās - This is a glorification, puṣpita vacah, flowery language. Did Gaura forgive Chota Haridās, Gopāl Chāpal, Mukunda? Jagāi and Mādhāi were redeemed by Nitāi, Devānanda Paṇḍit by Vakreśvara Pandit. What means mercy? A blanket pardon? A human right? Mercy means getting what you don't deserve, it is not an automatic hand-out human right. Devānanda and Jagāi and Mādhāi got the mercy (of Mahāprabhu’s associates) - it is rare, occasional and at random.

Exploiting the belief that "Gaura-Nitāi don’t take offenses" is itself a nāmāparādha - namno balāt yasya hi pāpa buddhih - committing sin on strength of the divine name. "Let me torture Vaiṣṇavas and afterwards say Nitāi-Gaura haribolo." Will Gaur forgive it?

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Vaiṣṇava: "If it were true that everyone chants nāmāparādha in the neophyte stage, no one would ever advance beyond that stage. Rather, everyone would fall down completely because of nāmāparādha.”

Advaitadās -
This is also wrong -

nāmāparādha-yuktānāṁ nāmāny eva haranty agham 

aviśrānta-prayuktāni tāny evārtha-karāṇi ca 

(Hari-bhakti Vilāsa 11.526 )

Constant chanting may dissipate nāmāparādha.

One can chant nāmāparādha (not nāmābhāsa) if you follow an aparādhi guru. That isn't conscious nāmāparādha as long as you are innocently deluded by an aparādhi guru. It is institutionalized nāmāparādha. If you understood that the Guru is an aparādhi but you keep following him because he heads a comfort zone, then it becomes nāmāparādha. How to get rid of it? Reject the aparādhī Guru. How this happens? If Krsna mercifully sends you an offenseless Vaiṣṇava who opens your eyes about the offensiveness of that Guru. As Vakreśvara Pandit enlightened Devānanda Paṇḍit. One gets to the śuddha nāma stage by the kripā of Sādhu, śāstra and Guru (Bhagavān) and it's very rare

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The 9th offence to the divine  name is generally presented as " To instruct a faithless person about the glories of the divine  name."

But the text extends it to any preaching at all, about anything, to the faithless. The divine  name isn't mentioned in the text.

aśraddadhāne vimukhe’py aśṛṇvati yaś copadeśaḥ śiva nāmāparādhaḥ [Hari-bhakti Vilāsa 11.523].

Sanātan Gosvāmī's dig-darśinī-ṭīkā says -

aśraddadhānādau jane ya upadeśaḥ sa śiva-nāmni aparādhaḥ | śrī-bhagavatā saha śrī-śivasyābhedena śivety uktiḥ

It is an offence to preach to the faithless in general , about anything, not only about harināma. Sanātan Gosvāmī confirms here by the way (“The name Śiva is used here due to Śrī Śiva being non-different from Śrī Bhagavān”), that the 2nd offence to the divine name is not to see Śiva as independent from Viṣṇu but as separate, what to speak of "To consider the names of demigods like Lord Śiva or Lord Brahmā to be equal to, or independent of, the name of Lord Viṣṇu."

Sādhu Bābā translated the 9th [8th in his counting] offence as ৮) শ্রদ্ধাবিহীন জনে ও শ্রবণবিমুখ জনে উপদেশ করিলে অপরাধ হয় – “If you instruct a faithless person who is averse to hearing, it is an offense to the divine  name. “ There is no mentioning of the glories of the divine name alone, it says ‘instructing on anything’.

The 10th offense is discussed here -
and the 2nd offence is here and here