1) Thoughtful explanations go a long way! Give them the small gifts and attach a note to the effect of "I am a very autistic person and I sometimes seem strange to people. I hope that is not the case with this gift. I simply wanted to give you this gift as a token of my sincere appreciation, I hope the gift is received in the spirit it is indended."

2) Don't say the word love whatsoever to these people. Probably shouldn't even think of that word in this context. Adoration, respect, admiration, are all appropriate in an academic environment. Saying the L word in this context is almost never appropriate and could get you into trouble, especially if you're already awkward anyway.