(1) I, as well as many others, do not treat Gen 1 as creation ex nihilo. I
believe that v. 1 is either a titular or summary statement for the entire
chapter, that v. 2 is the background setting for the creation account, and
that v. 3 is the first act of creation. Alternatively, v. 1 could be seen
as a dependent clause, and either v. 2 or v. 3 as the first main clause (as
in NRSV and Tanakh). In either case, I don't believe the chapter is giving
an ex nihilo account.
(2) With regard to Ecc 1:5, what I presented was not eisegetical at all,
but simply a representation of the actual text:
(a) the sun rises
(b) the sun sets
(c) and hurries (lit. "pants") to return to the place from where it will
rise again
With regard to (c), how does it get back to this place without us seeing
it? By traveling under the earth during the night, as most of the ancients
believed was the case.