Most of us here chose a J-pouch over a permanent external ileostomy. A J-pouch adds complexity and a longer list of things that can go wrong, but it has substantial advantages (when all goes well) in terms of body image and independence (e.g. from ostomy supplies). The only time an external ostomy would have been more convenient for me was when I had to deal with an asian squat toilet, which will one day make an amusing essay. Some people go directly to an external ileostomy and never look back.

I'm not sure if your prior disease has any effect on the likelihood of a successful J-pouch. In any case, I hope your distal anastamosis (typical reversal) is successful. Good luck!

I think you'll find a wider range of BMs for our population than "4 bowel movements a day."  If you make that your expectation, especially early on, you will likely be disappointed.  I started at about 10+ a day, at first, with nighttime awakenings, until I deferred going and slowly the pouch could hold more and more. A "fresh" pouch, as I've been told, holds about a pint at a time. What you eat influences the number of trips, too. There's a big learning curve. 

I'm nearly 25 years in, and while I generally sleep through the night, my daily BMs fluctuate with a likely mean of 6 a day, but between 4-8, roughly. I might go at night if I eat late or indiscriminately. However, even though I use the bathroom more frequently, I don't experience the desperate urgency of the colitis I once had.