So glad your partner is more understanding about little dogs.
Something you can do instead of lots of exercise - is lots of mental stimulation (what Newfsie was saying).
so lots of trick training - any trick will do... If you can spend about five minutes a day and maybe thirty pieces of something yummy - training your dog to do something from a nice stay to spins, begs, bark on cue, shake hands, roll over, play dead, its yer choice, collar grab (dog puts its neck in your hand when you put your hand out), fetch (hard for a terrier)... pick one thing then when that's good, pick something else. Google "shaping dog tricks" or youtube search kikopup - use the word "yes" instead of a click/clicker.
And getting your puppy to work for her food eg put it into treat balls - make sure you have at least one more treat ball than you have dogs (or separate the dogs while the treat ball is in use). there is a cheap treat ball that works quite well but melts in the sun or there are some more expensive ones like my favourite is a bob a lot. There is also one called a squirrel dude tho it tends to spit out very small kibble too fast. Or you can mix dry kibble with yogurt or water or olive oil and pack that into a kong and freeze it.
I had a friend who has Tenterfield terriers (also tiny) they take about an hour to eat a dried pigs trotter - my dog dispatches them in about 3 minutes.
If you know anyone with horses that they get shod - see if you can get them to save the hoof trimmings for your dogs to chew on (my dog loves these and they last a little longer than pigs trotters). I think you can also buy cow hoofs. I'm not so fond of pigs ears because they are quite fatty and can lead to tummy upsets....
Does your dog like carrot (you eat some then offer to the dog) - they could take a while to chew up (about a finger sized bit).
You could possibly get a shell pool and put some sand in that and bury toys or kongs with food in there. Then you can take it with you when you move... it will kill lawn if you put it on that. If the dog digs anywhere you don't want - I find the easiest way to manage that is to put a brick or something hard to dig in the hole. My dog won't dig her own poop either so I sometimes bury that into the hole.
Also - something that works about 12 hours - to stop cushion chewing - is vicks vapour rub. But you do have to reapply each day or each time you go out. It stings a bit to sniff - so discourages dog from chewing there. Aloe vera cactus or crib stop (equestrian supplies) also tastes horrid - even to a dog - so that may also help.
A lot of aloe vera eaten at once is bad for a dog but most dogs won't do that because it tastes horrid. I use it on wounds to stop licking and promote healing.