maxcitenames = 3, minnames = 3, in the
maxnames = 999, minnames = 3, in the
.bbx. This results in
maxcitenames=3, maxbibnames=999, mincitenames=3, minbibnames=3.
min<names> counter must always be less or equal to the
max<names> counter, so
maxnames=1, conflicts with the min settings of
3. So you will have to change both
You would use
to change the citations only.
In the discussion below it emerged that you want to change (primarily) the behaviour in the bibliography, so
should give you what you want. As that changes both
maxcitenames (for citations) and
maxbibnames (for the bibliography) and
mincitenames (for citations) and
minbibnames (for the bibliography) respectively.
natbib=true enables the
natbib compatibility mode. You can then use
\citep as alias for
\textcite. Additionally some of
natbib's cite alias feature is implemented. Note that the starred versions of the cite commands differ between standard
natbib mode. (See also §3.8.9
natbib Compatibility Commands of the
biblatex documentation and Is there a disadvantage to using natbib=true with
If you don't need
\citet as alias for
\textcite, you probably don't need
Ad 3) What is the "best" style is a purely subjective choice. If you happen to write for/under the supervision of anybody (that includes thesis instructors, publishers, journals, ...), the best style is what they tell you to use. If you don't have any instructions on style use what you like best or what seems to be the norm in your field.
 Sigfridsson and Ryde 
Aksın et al. , Baez and Lauda , and Worman