No.1
It could work, I guess; it's just that verbs of perception don't seem to collate with scarcely all that frequently.
No.2
Ex: You had rather I didn't tell her about it, hadn't you? 
=> The two hads express different meanings.
No.3
Ex: Plants grow when there is air and sunshine.
=> It's colloquial, but awkward for Standard English; i.e., (at a time) when ...
Ex: Plants grow if there is air and sunshine.
=> This could work if, that is, you want a conditional reading;i.e., only if there is air and sunshine.
No.4
Ex: When people are fearful about the future, they look for escape," comments the president of the association.
=> to be fearful of something means that you feel that that something can harm you.
=> to be fearful about the future is a collocation. (The future can't harm you.)
Ex: In a cinema, with a 65-foot screen, you lose temper for two and a half hours. 
=> the key "temper" has me stumped also. I haven't heard it before.