For the first problem, the simple solution is to merge the cells containing the address into a single cell. Then, assuming address fields 2-4 may or may not have data, you'd put them all on a single line with address field 1, thus:
«Address_Line_1»«Address_Line_2»«Address_Line_3»«A ddress_Line_4»↵
«Address_Line_5» «Postcode»
where ↵ is a manual line break to keep «Address_Line_5» «Postcode» on a separate line. Then for each of address fields 2-4, you'd use the mergefield \b switch to conditionally output line breaks when those fields have data. To do that
• select a given mergefield (e.g. «Address_Line_2») and press Shift-F9 to expose the field code, which will look like:
{MERGEFIELD Address_Line_2}
• edit the field code so that you get:
{MERGEFIELD Address_Line_2 \b "↵
"}
where ↵ is a manual line break.
That's all there is to it. Now, when you merge, only the lines with data will be output.

As for the second problem, you only need to switch off the 'fit text' and 'wrap text' options, which you've added to some cells. You also need to delete the extra paragraph marks from those cells and give the rows concerned an 'Exact' height setting, rather than the present 'At Least' setting.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]