The blocked process threshold is not going to catch deadlocks. It's there to report long-term blocking where the blocked session waits longer than the threshold you've configured (5 seconds there)

For...

If compilations are high, you may want to investigate why cached plans aren't being reused. It's not an automatic 'you are under memory pressure' though.

http://www.sqlservercentral.com/articles/Administration/64582/

http://www.sqlservercentral.com/articles/Transaction+Logs/72488/

Do log backups more often.

Probably because it's waiting for the...

Shrink releases free space in the file...

It's a modification to the database. It is logged. So's shrinkfile. ALL...

d) Rebuild...

Please don't do that. Horrible practice.

If you manage the log properly, you won't need to shrink it. Please take a read through http://www.sqlservercentral.com/articles/Administration/64582/

It removes every single cached plan, So next time the queries run, they have to go through the expensive compilation process again.

It is NOT something that should be run on...

Yes.

The majority of the memory usage on an instance is not going to be by the queries, it's going to be the buffer pool, the data cache should be the...

Start by investigating what changed.

Also bear in mind that a single counter is almost never useful by itself. If the latch waits/sec changes, what else has changed, in what way....

It's PHP.

If they aren't blocking anything, then it should be pretty safe to leave them be. Just watch that there isn't an open tran registered for any of them that could...