In general mincemeat has already been cooked and the suet distributed. The recipe you link just happens not to on the assumption that it will be cooked later, and it doesn't keep nearly as well as most recipes, because the apple isn't cooked.
I used to make this Delia Smith recipe which gently cooks it, then you have to stir as it cools. I used to make a batch every other year, that's how well it keeps. It's also far better than bought mincemeat (I used to buy the pastry but make the mincemeat for my mince pies. The other way round is far more common but my hands are too hot to make good pastry.)
Commercial versions do sometimes have visible bits of suet despite being cooked (probably because stirring during cooling isn't possible when it's packed hot). If starting with such a commercial jar, or the recipe you linked, I suggest warming it through, then stirring a few times as it cools, before using the cooled mincemeat in your cheesecake.
Another option if you were making mincemeat specifically to stir into a cheesecake would be to simply omit the suet. Although it's a decent fraction of the ingredients, you wouldn't miss it in a cheesecake. If the mincemeat is used in a layer, the suet might be needed to stick it together, then (assuming a biscuit base) you could spread it on the base before it's fully cooled.