All right youse wise guys, keep it up and I'll never play for you. That'll fix ya.
Is your friend set on Highland pipes? While the sound is haunting and loud, will all respect due them, they are limited. Who else plays in Bb?
A practice chanter is a good way to start. Catspaw's inevitable reaction aside, I've got an electric practice chanter which I really lilke. It's quite portable, fingers pretty realistically, and can be played through headphones, thereby reducing mileage on the wife and cats.
Other than Great Highland Pipes, they are some interesting ways to go. You've noted Uillean pipes which often play in G or F and produce a lovely, lyrical sound. They're bellows blown, adding another element to their operation which can be good or bad, depending on one's wind and/or upper body strength. Uilen pipes play at fairly high pressure, so they can be a handful (or armpit full). They can be hard to find in the states, and pretty costly, especially for a full set with keyed drones.
Northumbrian pipes are far and away my favorite. They have a sweet, liquid tone and play only about as loudly as a fiddle. Their bellows blown low pressure (about 16" of water) makes it easy to sound them. The definitive tutor on Northumbrian pipes is written by a guy in Texas named John Liestman, it's well worth a look at his website. I've got a set of Liestman pipes I'm learning to play and I'm having a great time. Nothrumbrian drones(up to four on a set) can be shut off so that you're playing only the chanter, a nice feature for practice. Northumbrian smallpipes are often found in F or G, sometimes D.
A great beginnner's pipe is the mouth blown Liecestershire small pipe. Single drone, medium sized bag and it's quiet. Mine have as split stock for a D or G chanter.
Allow me to recommed these men, all of them are listed in search engines, are friendly and responsive and have very informative websites. John Liestman for Northumbrian pipes and links; Philip Gruar for Northumbrian pipes; David Marshall at Ancestral Instruments for historical pipes and strings with sound samples; Ray Sloan for Uillean pipes, Scottish smallpipes amd flutes with sound samples; Julian Goodacre for English pipes and recordings.
Good luck to your friend. It's a great adventure. Pay no attention to the wiseasses behind the curtain.