ad te instead of tibi is, if you must know, a sign of linguistic innovation in Latin, whereby head-last constructions were reversed by the replacement of case forms with a semantically equivalent particle, a general progression that resulted in the continual growth of the preposition and head-first constructions as witnessed in Romance tongues. it is palpably untrue to think that Latin progressed by the shift towards inflections (as was stated in the thread you linked) rather than augmenting them with prepositions.
i thought you were going to say ad te is used for apud te in Cicero’s letters, which is perfectly true and does have archaic origins but can be found in Livy and Phaedrus.
not sure what is wrong with Latine: are you treating it as an object rather than an adverb? i don’t know too many adverbs that decline.
athematic uolt (<*uel-ti) actually left élite Latin a lot later than one would think. Sallust uses it with no particularly archaic flavour. the process of o>u before a velar+consonant was still unfinished in the beginning of the first century B.C. and Catullus and Lucretius, to name two, almost certainly would not have succumbed to it. Catullus wrote, of course, quoi dono lepidom nouom libellom, also exhibiting the not yet complete shift of closed o>u after non-u.
the retension of g (as velar nasal) in *gn- stems is attested into the Classical period but is, of course, more prolific in earlier centuries of Latin (cf. Varro fr.330 on Gnaeum: qui g littera in hoc praenomine utuntur, antiquitatem sequi uidetur). the point is, however, that one cannot say that “Ennius used ancient words ergo he wrote in ‘an ancient style’” because it is palpably false. Ennius wrote in the manner suitable for poetic diction at the time which, rather than being retrospective of literature preceding him (of which, save a few fragments, we have nothing), seems to suggest full utilisation of the language of the day. so yes there was a poetic style but nothing anachronistic for himself. it only makes sense to impose the term ‘ancient style’ if someone writes in a purposefully archaising manner.
the Latin of de Bacchanalibus is not especially old (roughly coeval with Plautus). how about these?
Manios med fhe fhaked Numasioi (c. 600 B.C.)
iouesat deiuos qoi med mitat, nei ted endo cosmis uirco sied | asted noisi ope toitesiai pacari uois. | duenos med feced en manom einom dze noine med maao statod (c.550-500 B.C.)
as for my comment regarding the larger gap between Cl. and Med. Latin than Shk. and MoE, i do not have the interest to type out a long list of why this is so. you do not have to believe me, but i simply cannot see how one could compare the standard primers of the two periods of Latin and not find that the shift in Eng. from Sks. to MoE is so small to the extent of bizarre.
~D