don't touch others?
It is less likely - yes.
man touch polish man, he will think "wtf are u doing"
Probably, but it may depend on circumstances.
Yes - a hug, a touch from a nice girl - why not, but touching back - maybe not so fast.
very poor dictionary about expressing feelings?
Ehhm - some other words exist like 'ubóstwiam Cię', 'miłuję' (this one is a bit outdated), but 'kocham' is the most universal and common.
"Bardzo zabawne", his talking partner will think that he uses an irony.
Yes - the best would be just a spontaneous laugh :)