Introns and terminators

[J.S. Good]

Dear Reader

A few questions :

1. Are there any consensus sequences for 5' and 3' intron splice sites,
and if so, what are they?

2. Is there a known minimum intron length?

3. Will hairpin loops (such as the T7 terminator) disrupt EUKARYOTIC
transcription/translation to a great extent? 

Here's were all this is going : could any disruption of translation be
ameliorated by placing such a structure between intron splice sites?

Thanks for any info!

James