I have a working INDEX lookup function using an array, however due to the data size it takes too long to produce results using arrays
{ IFERROR(INDEX(Notes!$B:$B,MIN(IF((Notes!$A:$A=$A2)*(Notes!$B:$B<>""),ROW(Notes!$A:$A)),9^9)),"") }
This will lookup lookup cell $A2 in Notes!$A:$A column...