Ergativity, accusativity, activeness and ebisedicity

While writing the grammar page (and designing the grammar) for Pidse and
getting influenced by Georgian, your favorite language, I came up with
this horrible system. Is it within the bounds of okay? Is my terminology
all good? Is there another/better term for ebisedic? (I don't think it's
close enough to the Ebisedian system, but I'm willing to be proved
wrong.) (What follows isn't straight out of the webpage; there are some
changes here and there. Oh, and the aspectualised/modalised/aorist[1]
sentences have more relevancy elsewhere in the grammar, too.)

[1]: I came across the word 'aorist' when trying to find 'aortist' in
various dictionaries and being told it didn't exist. What does aortist
mean?

Pidse has four different ways of determining what case the subject of a
sentence will be in: an ergative mode, an accusative mode, an ebisedic
mode and an active mode.

Pidse has three tenses (past, present and future), three aspects
(perfective–cessative, progressive and inchoative), and three moods
(irrealis, possibilitive and realis). How a sentence is constructed
depends on what the focus of it is: if the speaker wishes to stress the
aspect, an aspectualised sentence is used; if the mood is to be
stressed, a modalised sentence is used, or if they wish to stress the
time, an aorist sentence is. Modalised and aspectualised sentences may
be classed together as 'defined sentences'; aorist sentences are
sometimes more transparently called 'undefined sentences', but that is
what 'aorist sentence' means, anyway. (Modalising or aspectualising does
a sentence does not rule out using tense or aspects or moods on the
verb.)

Furthermore, there are four categories of verbs (which are then
subdivided into different classes). Category 1 verbs are transitive;
category 2 verbs are transitives which can be used intransitively;
category 3 verbs are intransitive; and category 4 verbs are ebisedic
verbs of motion.

Category 1 verbs pose the least trouble. The subject of category 1 verb
will always be in the ergative–nominative case; its object will always
be in the absolutive–accusative case.

Category 2 verbs, when used transitively, behave exactly as category 1
verbs. When used intransitively, the case of the subject is determined
based on the intention of the act: if it was intended, the
ergative–nominative case is used; if it was not, the
absolutive–accusative case is. It does not make sense for a category 2
sentence to be aorist (because there is obviously some modality), so
they're always defined. Some dialects treat the intransitive use of
category 2 verbs as they treat category 3 verbs.

Category 3 verbs are intransitive. Category 3 sentences are ergative
when the sentence is defined and accusative when it's not.

Category 4 verbs are yet more complicated. When the focus is the subject
and it is a pronoun, the ergative–nominative case is used; or when the
focus is the subject and it is not a pronoun, the instrumental case is
used. When the focus is not the subject and it is a pronoun, the
absolutive–accusative case is used; or when the focus is not the subject
and it is not a pronoun, the instrumental case is still used. If a
location is the focus, it's in the locative case; otherwise, its in the
relevant case out of inessive (dative for pronouns) and exessive
(pronouns cannot be used here). Not all parts need to be included in a
sentence. Category 4 verbs are all of motion; such as walking, driving
or travelling. Some dialects treat category 4 verbs as category 1 verbs.

(The reason for the different treatment of pronouns in with cat4
sentences is because there are fewer pronominal cases.)

So basically:
S=subject O=object EN=ergative/nominative AA=abs/acc U=unfocused
F=focused I=initial location D=destination

category 1=S: EN; O: AA
category 2=transitive: S: EN; O: AA
           intransitive: S: EN (if intended) AA (if unintended)
category 3=S: EN (if sentence is undefined)
           S: AA (if sentence is defined)
category 4=US: Instr (if available), else AA
           FS: Instr (if available), else EN
           UI: Exessive or none
           FI: Locative
           UD: Inessive (if available), else dative
           FD: Locative

So what do you think? Are category four verbs close enough to Ebisedian
to be ebisedic, or is there another language out there that has
something more similar, or is there another term?

Tristan.