low intensity cardio will help speed up fat loss for sure, but some prefer to add this in when fat loss slows. it all depends on how fast you want the weight to come off, and the possible risk losing excessive strength/ muscle mass. i find its always good to have a few "tricks" to add in when fat loss seems to stall, i.e. supplements, cardio, macro manipulation.
i'd say since you are fairly sedentary other than in the gym, cardio will be good. fasted morning cardio is very effective at reducing stubborn body fat. i like to keep my heart rate below 130 but above 110.
how fast can you expect the fat to come off? that really depends on how much fat you carry right now. the more fat mass you have, the faster it will come off. try to maintain consistency for a good 8 weeks. go all in and you will be pleased with your results no matter how heavy you are starting out.
i use a fasting approach and strictly stick to very clean calories but every week I have a SERIOUS cheat meal after training on Friday night normally consisting of 2 five guys burgers and fries or 2 chipotle burritos, chips and guac, or some type of American or Chinese buffet. this approach has kept my morale high throughout my entire diet and I have not fallen off the boat.
like i believe facko mentioned in a previous post, i also like extending the fast a bit longer on non training days. today i actually fasted for about 22 hours and had a very satiating meal of about 2000 calories, lol.
the last bit of advice i will mention is that I like using a glucose disposal agent of some sort when i'm eating a big meal of carbs. this doesn't have to be an expensive supplement. A couple tablespoons of apple cider vinegar or some cinnamon powder about 10 minutes before I eat.
have fun fasting! i don't miss eating small meals at all.