I'm glad to have found Ballantyne's edition of the Mahābhāṣya with Kaiyaṭa and Nāgeśa's commentaries, in the Digital Library of India collection. The edition is from Mirzapore, 1855 (bibliographical details).
Here are some representative pages from it:
Title page:
Mahābhāṣyam
bhāṣyapradīpena vivaraṇena ca sahitaṃ
kāśyāṃ rājakīyapāṭhālaye śrīmadvālaṇṭainnāmaka-
***
śrīnārāyaṇaśāstridevadatta-
durgodattaśarmabhirvyākaraṇapaṇḍitaiḥ
śrīmaccaturvedahīrānandaśarmabhir
alaṅkārapaṇḍitaiś ca saṃśodhitaṃ
sāṃkhyaśāstrādhyāpakaśrīmatkāśīnāthaśāstribhir
nidhyātaṃ
***
mirjāpurapattane trivedidurbaliśarmaṇā saṃśodhya mudrākṣariar upanibaddhaṃ
bhāratavarṣīya-
paścimottarapradeśādhyakṣaniyogān mudritam
// san 1855 īsvī //
So now we know that Ballantyne was aided by Nārāyaṇaśāstrī [and?] Devadattadurgodattaśarmā, specialist(s) in vyākaraṇa, and with Caturveda Hīrānandaśarmā, an alaṅkāra paṇḍit. These pandits
edited the text. The sāṃkhya professor Kāśīnāthaśāstrī reflected upon the
text (nidhyātaṃ), which presumably means that he edited the text for content.
The text was edited and typeset in Mirjāpurapattana by Durbaliśarmā.
And here are the first two and the last pages of the text:
