Template to create a URL for Power Query to make a API Call for Federal Reserve Economic Data (FRED)

I've been able to create formulas for the top 3 rows in the original post. The field names have also changed. Here's a snapshot:

I had to post a snapshot because the formulas require a key which I didn't want to post. Here are the formulas. Be aware that FAKEKEY is a named range for the required API key. In the formulas below it is set to

Excel Formula:

="api_key=abcdefghijklmnopqrstuvwxyz123456"

The formulas for B1:B3 are as follows:

Excel Formula:

=FILTERXML(WEBSERVICE("https://api.stlouisfed.org/fred/series?series_id="&$B$4&"&"&FAKEKEY), "//series[@id='"&$B$4&"']/@"&LOWER(A1) )

Excel Formula:

=FILTERXML(WEBSERVICE("https://api.stlouisfed.org/fred/series?series_id="&$B$4&"&"&FAKEKEY), "//series[@id='"&$B$4&"']/@"&LOWER(A2) )&", "&
FILTERXML(WEBSERVICE("https://api.stlouisfed.org/fred/series?series_id="&$B$4&"&"&FAKEKEY), "//series[@id='"&$B$4&"']/@seasonal_adjustment" )

Excel Formula:

=FILTERXML(
WEBSERVICE("https://api.stlouisfed.org/fred/release/sources?release_id="&
   FILTERXML(WEBSERVICE("https://api.stlouisfed.org/fred/series/release?series_id="&$B$4&"&"&FAKEKEY),
"//release/@id")&"&"&FAKEKEY), "//source/@name")

Note that all of the cells in column A use the custom format
#,##0.00;-#,##0.00;0.00;@": "
which adds a colon and a space at the end of text which is right aligned. I changed the names of the first two items so I could use them in the formulas and they better reflect the data itself.