which wp installation will avoid issues with wpml?

hi all

i have a general installation question. in the past, i (and according to many forum entries, many others as well) have noticed some issues with wpml translations when changing the standard language of the wp installation. as i’m now working on a brand new project, i would like to know, what the installation recommendations are?

as i have identified several ways to install a multi languages wp installation (not a multi site), i would like to know, which way of installation will most likely avoid future issues with the wpml plugin?

(i have downloaded always the available wp 4.5 versions provided by the mentioned websites below)

1. standard – installation (install wp from wp.org, which is us_en only and add later additional languages manually):

there is the standard wp download available on https://wordpress.org/download/ which provides a clean installation of wp, just with the us_en language option in the language dropdown menu at the bottom of the wp general settings page. there is also no wp-content/languages folder with any .mo/.po files available. one would assume that at least the en_us.po and en_us.mo files should be in there, but this is not the case.

it also contains the translation template (.pot) files for the standard themes twentyfourteen, twentyfifteen and twentysixteen in the wp-content/languages/themes folders:
wp-content/themes/twentyfourteen/languages
wp-content/themes/twentyfifteen/languages
wp-content/themes/twentysixteen/languages

additional languages can be added manually by creating the wp-content/languages folder and putting in the required .po and .mo language files (download from https://codex.wordpress.org/Installing_WordPress_in_Your_Language). the languages added to this folder will result in showing up in the language dropdown menu at the bottom of the wp general settings page.

2. language related installation (using a language customized wp installation download)

there are several language depending wp installation downloads available under https://make.wordpress.org/polyglots/teams/. i have installed the german zip files.

it also contains the translation template (.pot) files for the standard themes twentyfourteen, twentyfifteen and twentysixteen in the wp-content/languages/themes folders (this is also the case in the above described installation procedure no. 1) :
wp-content/themes/twentyfourteen/languages
wp-content/themes/twentyfifteen/languages
wp-content/themes/twentysixteen/languages

this installation provides the de_de AND us_en options in the language dropdown menu at the bottom of the wp general settings page after the installation. again there are no en_us files in any of the folders (like there aren’t any en_us files existing in the above described installation procedure no. 1 neither).

additionally, this 2nd installation version creates the language folder wp-content/languages containing 4 sets of .po/.mo files (admin-de_DE.po/.mo, continents-cities-de_DE.po/.mo, admin-network-de_DE.po/.mo and de_DE.po/.mo) and the folders plugins (containing the translation files for the standard akismet plugin akismet-de_DE.mo/.po) and themes (containing the translation files for the standard themes twentyfourteen-de_DE.mo/po, twentyfifteen-de_DE.mo/po, twentysixteen-de_DE.mo/po).

the analysis of the two installations procedures mentioned above raised following questions:

A
there is no translation template (.pot) file existing for the akismet plugin which is included by default in both above described installation versions. the 2nd installation does contain the translation files akismet-de_DE.mo/.po, but no according translation template file, isn’t such a .pot file needed?

B
why are there no en_us files (.mo/.po/.pot) existing at all (not for the wp itself, not for the themes, not for the plugins) in neither of the two installations?

C
which of the two above mentioned installation procedures shall be followed to avoid issues with the wpml plugin?

D
does the answer on question C depend on one of the following criterias:
which is the default wp backend language and which is the default website language?

thanks

silvio