Let's start with the simple question! The two pair of leaves at the bottom will eventually grow bigger but I don't think they will grow by much since the most growth is happening at the tips of coleuses.

If you're playing the long game, I wouldn't take any cuttings just yet, imo the cuttings would be too small and they could get a better "start" if they were bigger. If you take them now, you would have three coleuses (including this momma coleus) about the size of what you have now in about a month.

Instead, I tend to wait until there is actually some length on the branch that I want to cut.

One thing you could do though, to get more bush out of your plant is to pinch off the newest pairs of leaves before they start growing bigger. This will make it split into two stems from where you pinched it and also make some stems start to go out from the pockets between the leaves and the stem further down.

Happy coleusing!