Introductions are just a part of being a rat owner. I do new introductions once every year or two. I understand being nervous about it but it's a necessity to keep our rats from being alone.
It would be great for you to take on your friends' solo rats but your under no obligation to do so. If you'd feel more comfortable getting a pair of young rats to introduce to Templeton, that's okay. You can tell your friends that you don't feel confident enough to do introductions with adults.
Either way, you need to find a pair of rats asap to introduce to Templeton. Rats, especially young rats, shouldn't be alone for extended periods of time.
It would be great for you to take on your friends' solo rats but your under no obligation to do so. If you'd feel more comfortable getting a pair of young rats to introduce to Templeton, that's okay. You can tell your friends that you don't feel confident enough to do introductions with adults.
Either way, you need to find a pair of rats asap to introduce to Templeton. Rats, especially young rats, shouldn't be alone for extended periods of time.