You are welcome!

Does this work in the right sidebar for you? For me it does:

{{query (and <%current page%> (todo todo doing waiting))}}

P.S. delete the word "doing" if you don't want to see the DOING tasks.

Assuming you tag the top of an index as [[index]]:

1. Current page in indexes:

   {{query (and [[index]] <%current page%> (not (page <%current page%>)))}}

2. Indexes present in the current page:

   {{query (and [[index]] (page <%current page%>))}}

3. Notes about the current page:

   {{query (and [[Note]] <%current page%>)}}

4. Current page as "author" of something:

   {{query (property author <%current page%>)}}