An initial query about reciprocals

In the initial draft just completed reciprocals, I noted the following:

Reciprocal pronouns

Reciprocity is Vietnamese is usually expressed by nhau ('each other'). Ngô N. B. (1999: 175) provides the following examples (also LVSP), in which nhau occupies a position c-commanded by the matrix subject họ ([raised] object and indirect object positions, respectively):

7a. Họ giúp nhau làm bài tập. [EV: 175]
prn help eachother do homework
'They help each other do homework'

b. Thỉnh thoảng họ viết thư cho nhau. [EV: 175]
occasionally prn write letter give eachother
'Occasionally, they write letters to each other.'

c. Hai cái áo giống nhau nhưng một cái rẻ và một cái mắc. [LVSP: 325]
two cls shirt resemble each.other but one cls cheap and one cls expensive
'These two shirts look alike, but one is cheap and the other expensive.'

Nguyễn Đ. H. (1997: 137) mentions one other rather interesting example involving nhau, in which the reciprocal occupies the object position, and the thematic object is projected as a prepositional phrase:

8. Anh ấy kiện nhau với ông chủ. [NDH: 137].
prn dem sue eachother with prn boss
'He sued his boss (literally, he sued each other with his boss).'

Though (8) may be interesting, and (7) not unhelpful, there's a good deal more to find out. First off, I'd like to know what happens in other embedded subject cases, such as (i)-(iii) below.

[If these constructed examples are ungrammatical for some irrelevant reason, please excuse (and correct the idiocy), but the point should be relatively clear: is nhau licensed in finite complement clauses, in VP-complements to causative làm and làm cho? I'm assuming that these examples are all fine if nhau is replaced by a pronoun with disjoint reference.

(i) Họ nghĩ (là) nhau dã viết lá thư
prn think comp each other ant write letter
'*They thought that each other had written the letter.' [= 'They each thought that the other had written the letter.'

(ii) Họ làm nhau khóc.
prn make eachother cry
'They made each other cry.'

(iii) Họ làm cho nhau nhảy.
prn make give eachother dance
‘They made eachother dance.’

Any advice, thoughts, most welcome!

Stopping vs. Completion: a query about Aspect

Gage (1975: 258) gives the following examples to illustrate differences between Vietnamese and English with respect to the expression of Aspect:

1a. Anh ấy ngưng chạy [G: 258]
prn dem stop run
'He stopped running.'

b. Anh ấy ngưng học [G: 258]
prn dem stop study
'He stopped studying.'

c. Tôi không thể ngưng việc được.
prn neg-poss stop work can
'I couldn't stop working.'

2a. Anh ấy ăn lót lòng xong.
prn dem eat breakfast finish
'He finished eating breakfast.'

b. Tôi đã soạn đồ hanh-lý ra xong.
prn ant unpack suitcase go-out finish
'I've finished unpacking.'

[ Also, note:
Họ ăn đã xong. [G: 258]
prn eat ant finish
'They finished eating...which needs to be accounted for]

Observation: The predicates in (1) are all activity predicates, whereas those in (2) denote accomplishments or achievements. The expectation is that ngưng could also be used with the latter predicates as well; however, as in English, it should imply that the activity has stopped before completion (i.e. is temporarily suspended). Could someone please provide relevant examples?

Query: If these examples are representative, rather than a sampling error, they suggest that predicates to do with true telicity always appear postverbally, whereas 'quasi-aspectual predicates' that simply mark the edge (beginning or end) of an event (Travis' Outer Aspect?) appear preverbally. I have a sense that the syntactic options for the pre/post-verb lại bear this out. Does this seem to be on the right track?