First, while WC can create some very simple HTML pages, I don't think this is what you really need/want. Since you already know what I believe the place to looIndigo needs are XML files, you simply need to use the files you have without the values.
What you need to do is to create "blank" XML file (or files) for each one you want and then insert the WC "Web-Tags" where you want the actual value to be. Those "tags" are listed in the Manual starting around page 196 (for WC v3). Below I will take parts of the code you posted and show how to replace the values with WC tags:
...
<suggested_pickup>15 minutes after the hour</suggested_pickup>
<suggested_pickup_period>60</suggested_pickup_period>
<!--dewpoint_c--><!--3.3--><!--/dewpoint_c-->
<!--dewpoint_f--><!--38.0--><!--/dewpoint_f-->
<dewpoint_string>CD$<!--38.0 F (3.3 C)--></dewpoint_string>
<!--heat_index_c--><!--4.4--><!--/heat_index_c-->
<!--heat_index_f--><!--40.0 F (4.4 C)--><!--/heat_index_f-->
<heat_index_string>STAT_$_HEATINDEX:CURRENT_$_TEMPUNITS_$<!--40.0 F (4.4 C)--></heat_index_string>
...
<!--pressure_in--><!--29.359--><!--/pressure_in-->
<!--pressure_mb--><!--994.2--><!--/pressure_mb-->
<pressure_string>CP$</pressure_string>
<relative_humidity>STAT$EXTHUMIDITY:CURRENT$ %</relative_humidity>
...
"<!--" and "-->" are what I hope are the 'comment' labels. There is no need to change the constant values such as LAT/LON, etc.
You will note that some WC tags produce the same display in the format you want ["
CD$" and "
CP$"]. Others can be displayed using tags that need additional parameters ["
STAT$EXTHUMIDITY:CURRENT$ %"] the "%" is just plain text for whatever units you want. Lastly, some may not be exact matches to what you currently have: WC has you set the units such as mm or inches, mph or kph, etc. but not both at the same time.
Hopefully you can use the tags in the appendix and place them where needed in the XML files.
Then, you simply add these files to the WC prefs->On-Line->Custom Web->Additional Files. WC will, then 'grab' those files and replace the tags in them with the data gathered from your weather station hardware.
The real experts here can help with the other tags and parameters that I have neglected to provide. Just tell them what you need and they will be exceedingly helpful.