bnwg,

For smartsearch i'm pretty sure that it needs time to (re)build its indexes so just when you open Search app even if it was enabled it would need a few minutes to update its index. So I'm not too sure if its a good idea as you'll be getting old information anyway if its not updated.

Checking for WiFi connectivity you can simply write a sh script that pings google every X mins; if it failed then the script itself can disconnect the connection etc... The script can be run as nohup so it would keep running in the background but I'm not too sure if it affects battery consumption too much