(1) You simply need 1 query per insert, so just do it. :-) Now, if the problem is that you need to be sure that all the inserts succeed, then wrap the entire sequence in a transaction.
(2) Nothing special here, just say:
update table set ..... where ......
and if the where-clause simply happens to be true for 2 or more rows, then that's how many rows will be affected. As an extreme case, omit the where-clause and the update will effect every row.
