Since you are unexperienced with cigars, and also since I tend to be suspcious by nature, I would skip the ISOMS just in case. Unless of course you can rely 100% on your friends and their source up north.

The guys made some great suggestions.

The Cohibas (Dominican "Red Dots") are a great gift cigar and being Dominican are legal and easy to obtain and sure to raise an eyebrow with any cigar lover. The best man would be "wowed".

Gurkha - Ashton - AVO - Punch Gran Cru - CAO Anniversario - Arturo Fuente Hemmingway - Montecristo - Rocky Patel - Dunhill

All of the above are recognized mid to upper premium cigars by cigar smokers. Any of them would be great gifts for your best man as well.

For the ushers, believe me, stick to Macanudo - Mild, well made and popular for beginners.

Just be sure to bring the cases with you for sizing. Any good tobacconist would be eager to help you.

By the way....congrats on your marriage!