mjall

you can mount those fan (packs) anywhere as long as it fits - in case of replacement just watch the airflow hence blower/sucker - there is a small arrow printed showing direction.  
https://www.techpowerup.com/forums/threads/fan-direction.44512/

just put 1 (or 2) screws - should be good nuf  
 
TT fan connectors use 1 more pin  - TT wants you to buy the complete fan pack including controller