Well as I said, you can use any mince, as long as you account for the calories, so yes, the lean mince should work fine. If you want to reduce the calories further, you could use extra lean beef mince or even turkey mince.
Think once you get down to goal weight, it’s a case of trial and error, to see how your body hands the increases. I have found in periods of maintenance along the way, that I can keep reasonable control, as long as I stick to the principles of the BSD and largely avoid the bad carbs. I admit though, that small increases in weight occurred and that I haven’t actually don’t a proper period of maintenance at goal weight yet, so can’t say for sure how things would work long term. I am close to goal and so hopefully will be in a position soon, to find out how things work longer term.
There are lots of people on the forum who are in maintenance, so have a check around and see if you can glean a better answer from one of them. Try using the search box in the top right corner of the page, to look for specific topics.
Good luck Claire.