They need to be leash trained. Perfectly normal response from a puppy the first time you put on a leash. At this point don't try to really walk them. Attach the leash to their collar and let them drag it around. This helps them get used to the weight of the leash and it being there. Second step (and this is where you may have to throw all dignity aside and not mind being viewed as a complete idiot by your neighbors perhaps
), take some really fun soft treats with you - cheese is a good one; hold the leash in your left hand, cheese/treat in your right; stoop into a good Groucho Marx posture, let puppy smell the cheese and you begin walking backwards coaxing the puppy along with the treat. To get her motivated - in your best happy, upbeat voice call "puppy, puppy, puppy" to get her attention and for motivation. As she follows you along after the treat - throw in lots of "good girls, good puppy" and give her a bit of the treat and lots of praise. When she stops or balks, and she will - she's a baby puppy with a very short attention span and easily distracted; coax her with the treat and begin again.
Puppies shouldn't be aloof, they should be curious, inquisitive and pretty much into everything. Now with you getting the two litter mates, *you* probably aren't going to be as interesting as if you had just the one puppy. They still have each other and are used to the security of the bond they have shared all their lives.
With the two puppies, I will caution against leaving their collars on when you are not there to supervise. During wrestling type play, it is possible for one puppy to get their mouth under the other's collar, twist it and not be able to let loose resulting in the other puppy being strangled. This has happened with adult dogs also and collars needing to be cut off. In the worse cases, the strangled dog has died. So that's just a head's up.
Lots of patience, keep the sessions short, upbeat and fun and they'll catch on real quickly.
Debbie