J.L.
My twins were born on the day my oldest turned 20 months. It was overwhelming for me, but we got through it. My twins are now 2 years 4 months. My advice to them would be to find a support network of others with multiples, maybe even someone with another child or two. I had no luck with the local mother of multiples club in the San Fernando Valley (tried to join 5 times after their birth with no response), but I know others found the clubs very helpful. I've found groups on Cafemom for mothers of multiples where there are people with some good experience and advice.
As PPs have said, a schedule is key. In the early weeks, a schedule doesn't work, but once the twins are around 12 weeks, I would advise becoming very rigid with the schedule. I mean not just the feeding and nap schedule, but with when different necessary household tasks are done, when grocery shopping is done, when baths are dones, etc... I was fortunate enough to be able to hire help twice a week so that I could spend time alone with my oldest and get out of the house! If your friends can do this, I recommend it. Of course, if they have family or friends who can provide care for the twins, then all the better.
The multiple clubs sometimes have items for sale from other members. I used a double stroller rather than buying an expensive triple, but my oldest wasn't great about stroller riding anyway. Depending on how their 2 year old is, they could maybe attach a stand/sit thing to a double stroller. I think One Step Ahead had something like this. I found my infant slings and Baby Bjorn carrier invaluable when getting out with the kids. There is a double Snap-N-Go stroller that is really simple to put in a car. Two infant seats snap into the front-back base.
My husband and I committed to having a date night once a month. Sometimes, because of financial constraints and our exhaustion, this would just be a lunch during the work week, but it was still refreshing and necessary.
I wish I had tips on saving money - it's been an expensive couple of years for us. If your friend is able to BF the twins, that would be a huge money saver. Formula became very pricey. We bought formula, diapers and wipes from Costco, the Kirkland brand. Some stores have a discount for parents of multiples. It's always helpful to inquire.
At stores, I learned to push the double stroller in front of me while I pulled the shopping cart with my older child behind me. If you pull it from the front of the cart instead of the handle, it controls well.
Most of all, let your friends know not to hesitate to accept help. There will be a time in their life when they can return the favors, but for awhile, it will be their turn to receive. Good luck to your friends.