I've taken out a home equity loan and a personal loan that I have used to pay off other debt. Based on your post, it sounds like there is no reason why you shouldn't take out a loan at a reasonable interest rate and pay off the higher ones. However, I'm not sure what your definition of "bill consolidation".
It sounds like your taking out a personal loan with the intention of using the funds to pay off debt, but your not under any legal obligation to do so? OR is this a true debt consolidation, where the credit union will be sending the payments directly to your creditors and you will need to close out accounts?
I would also check with the credit union because depending on the type of loan it may not be just as simple as paying the additional $90 month. Also, if you can afford to pay $250 a month, then why aren't you taking out a loan for a shorter period of time where the monthly payments would be in that range? (taking out a $8,000 loan for 60 months vs. $8,000 loan for 36 months) Chances are since the loan is for a shorter period of time, you'd get a better interest rate.
Also, it sounds like your paying the doctor/medical facility directly. They should not be charging you any interest.
What is your credit score like? It sounds like you may have a decent credit score and have been making timely payments, but you just have a lot of debt. Have you tried contacting the credit card companies and reducing your rates?