I have a few suggestions for you to consider.

The Dobe needs to be socialized with other dogs her age and size, so she can learn her "doggie" manners. She is not able to learn these things from your Chi's as they are too small to do things like a body block to her, to stop her from doing stuff.

You can do this through obedience classes (which I highly recommend with a Dobe!), or through doggie play dates. Try www.meetup.com, see if there is a dog play group meeting near you for her size dog. If you find one, it is free to join meetup.com and then you join the group you are interested in so you receive email reminders of the meeting dates. You need to be sure to use the RSVP function so they know how many to expect at a given play date.

You could also try craiglist under Pets, but be cautious as you never know who you are connecting with on there. There are many good pet owners on there, but also some real nuts!

For the chewing (but NOT chewing on the chi's, lol), you have a chew toy ready to trade. You use a sound (ah-ah is the most common in training) and make disgusted noises. Have a nice little hissy fit, of disgusted sounds, to get your point across. No scolding, yelling or hitting the dog. Dogs do pick up on the tone and learn from that. Once she stops, move to another part of the room or the yard, offer her the toy in your hand and praise, praise, praise!

You have a wonderful pup, start now to help her grow into a well mannered adult dog!