The general consensus here is to get a bigger tractor than you think you’ll need. That opinion comes from the experience of many of us that already made that mistake, and ended up having to upgrade at some expense. You can include me in that list. The first tractor I bought, was a Ford 8n, it was the perfect tractor for my needs, at a reasonable price...Not!
For the size of your property, I would go with something in the 30-40 hp range. You should get over your disdain for emission controls, because that situation is going to get worse in the future, not better. There will be a time coming up when people will be relieved they bought a tier 4, before the the next layer of regulations comes.
As for mowing your lawn, you would be better off getting a dedicated mower of your choice, as tractors don’t treat a nice lawn well, and tall grass pastures don’t treat small tractors well
Not meaning to be harsh here, just passing on the fruits of my mistakes, hoping it will help you out.