I noticed your daughter is having bloodwork done next week, so I thought I'd throw in a few suggestions. Am assuming she will have a CBC and full CMP done. This posting addresses other tests that can be done. (Hope it's not too long-winded.)
But first, about surgery. It was mentioned early on in my daughter's case, as she has a stricture (much longer than your own daugher's), but we tend to fall into the camp of those who consider it the option of last resort. A permanent solution with the potential for only temporary benefits. Crohn's tends to recur. There can be complications. There might be no remission at all - they might not remove enough TI and/or the Crohn's might not be located only at the TI (the fistulas and abscess could point to this). At least one new medical therapy, still in clinical trials, shows signs of being less effective in patients who have had resections. My own daugher's GI uses the argument "do it now while you are still relatively healthy" to introduce stronger meds like Imuran...specifically, to avoid having to eventually have surgery. A stricture is by no means an immediate ticket to surgery. But for those who cannot get their disease under control even with the strongest meds, it can be a blessing. Now, on to the easier stuff:
CRP and sed rate (ESR) can be checked. At the first sign of inflammation, CRP levels tend to react faster than sed rate. BUT 25% or more of Crohn's patients might not have CRP levels that are responsive to inflammation. SO we check both.
Some research indicates low iron might be common in women of mentruating age. Also, meds can cause anemia. The disease itself can cause anemia - the anemia of chronic disease. A viral or bacterial illness can cause temporary anemia - the body sometimes "hides" iron if you have, for instance, a bacterial infection. The bacteria feed off the iron. So iron supplements should not be taken while somebody is suffering from either a viral or bacterial infection. Iron tests include: serum iron, TSAT, ferritin, TBIC. Together, they tell the whole story about iron. Serum iron fluctuates throughout the day, so it is the least useful test. Ferritin is the most useful, but it could be normal while TSAT is abnormal (which could signal a problem).
Low Vitamin D is common amongst Crohn's patients. The correct test is 25-hydroxy-vitamin D. If vit D is low, then an endocrinologist is your best bet for advice on supplementation. (Same goes for iron.)
Prednisone and Entocort can interfere with vitamin D and calcium absorption. Pred can cause blood sugar to rise - while on pred, a blood glucose test can be requested.
Optimal B12 is in the 500s and above. The B12 lab test should not go below 400 - if it is below 400, then oral supplementation should be started. If it is below 300, then a B12 deficiency can be presumed and the fastest way to get the B12 is probably through a shot.
Flagyl might have helped your daughter, but it can cause side effects like fatigue (which should be resolved once off the med).
In my daughter's case, iron plummeted while she was on 4000 mg Pentasa and resolved after being taken off the med - in all fairness, it should be noted she developed mononucleosis within six weeks of starting the med - mono has such a long incubation period that it could have altered lab results even when there were no mono symptoms present. While the manufacturer of Pentasa admits to field reports of anemia caused by Pentasa, it notes that it has not found anemia as a side effect in clinical trials run on the med.
We get a copy of every lab test and with the help of www.labtestsonline.org figure out what it means.