8-year-old poodle mix with chronic urinary/fecal accidents, pancreatitis, anxiety, etc. what else can we do?

My wife and I took in our now 8 year old poodle mix a couple of years ago. This was my wife's family dog that (due to family situations I won't get into here) we decided to take in since he wasn't being super well taken care of and was often being kept in his crate most of the day.

For context, We know he is a poodle mix of some sort but we don't know the other half (we think Bichon maybe?). He is very small and likely weight about 5 lbs. Our dog was 6 years old when we took him in, and my wife and I were childless at the time, but we now have one kid and another on the way. Our dog has had lifelong anxiety that we've tried to manage with anxiety treats, pheromone spray, and medication (which hasn't really helped). He also has significant dental problems, likely stemming from not receiving adequate dental care from her family before we took him in. We brush his teeth, but we're at the point where brushing probably isn't going to reverse the existing dental disease, and our vet has mentioned that he will likely need some teeth removed.

More recently, we took him to the vet because he wasn't eating much and discovered that he has pancreatitis. He's been prescribed medication and we're making sure he only eats his prescribed low-fat/sensitive-stomach food.

The biggest ongoing problem though, are his urinary and fecal accidents.

He was crate-trained as a puppy by my wife herself before she left for college, so we know he is trained. We put him in his crate at night after taking him outside immediately before bed. Despite this, he frequently urinates and sometimes even defecates in his crate overnight. This has happened more times than I can count in the past 3 years.

He also sometimes urinates or defecates inside the house while he's out of his crate during the day. We've tried establishing a routine and taking him outside as regularly as we can, as well as training him to use a Bluetooth doggie doorbell to tell us when he needs to go out. Unfortunately, he never consistently learned to use the doorbell despite the training. He's scared of doggie doors, and we don't have room for one in our small house anyway. Also, he does not constantly leak urine... rather, he is capable of holding it for periods of time but will often just go all at once without alerting us.

We've tried belly bands to prevent urine from getting everywhere, but sometimes he still manages to soak through them, and his thick fur becomes completely saturated with urine. Obviously, a belly band doesn't help with fecal accidents either.

My wife and I are tight on money. We both work (I'm full-time and my wife is part-time), and with a toddler and another baby coming, we're trying to figure out what we can realistically do to help him further, without spending money on things that aren't likely to help (we have spent so much money already on other things to try to help him).

What would you recommend we investigate for him? Are there inexpensive management strategies that might make this more manageable? Is there anything about this combination of symptoms (anxiety, chronic urinary/fecal accidents, pancreatitis, etc.) that stands out as something we should investigate further? What should we do?