Actually, BST and SMN duo's work just like BST duo's, the only difference is the SMN has more MP than you and doesn't have to deal with mischarms.
If you guys are going to strictly duo, I recommend this:
Don't think of it like a regular party. If the SMN is going to be duoing with you she isn't going to need craptons of MND+ gear to help with cures, on the contrary, it would be better if she has a crapton of +MP gear to assure that she can leave her avatars out longer.
As for BST, you would merely follow normal BST soloing protocol. Kiki is right about not really bothering to charm pre level 10, because it is honestly faster to just kill straight off than to worry about pets. However, 1-10 is a nice place to learn how to use charm, test your macro's, and learn a bit about BST before you have to deal with a lot of exp loss from death.
At 23+ I wouldn't use jug pets. While you don't get any exp loss from them, I somewhat doubt that a jug pet and an avatar would last long enough to keep chains going. They have lower defense, HP, accuracy, and attack than a normal pet so they tend to die quickly. They also can only be called every 5 minutes. Only time you should worry about them besides a true exp party is for farming or saving your ass.
I also recommend you don't use any melee food. You'll already have a hard enough time with pets keeping hate (even avatars) pre 30, so making it so you hit harder will only make that problem worse. If you want to use food stick to MP+ stuff like pies. Refresh drinks are cool too, but keep in mind that they can be expensive and really bog down your inventory. In fact I recommend that instead of using them you learn to be more efficient with your MP. Learn when to rest, when to not rest. If you have to rest during battle do so, since your pet will be doing most of the fighting anyhow.
If you're looking for specific information on how BST does their thing you can check the Allakhazam.com BST forum, they have a buch of resources there available to help teach you the job and allow you to learn what you need to survive.
Edit: Looking at the post was made before I posted this: Try to stick to EM-T mobs at all times, at least until your pets start to get a bit stronger and you can take down T-VT mobs. Don't worry too much about chains, because it's always hard to get them at lower levels. Let the pets do the work, Melee when you have to to assure that the pets will survive, but if you pull hate disengage your target lock and turn around until the pets are tanking again. BST can chain because they don't tank, their pets do. It's no different in a duo.