I would keep the muntins, the same number and look, as it is original to the style of the home..

Same number of lites as currently there now, maybe lose the picture window grilles. Are you using a removeable grille? Simulated divided lites or Grids between the glass?

No removable grill.

I was hoping to do simulated divided lites.

I think you are talking about mullions? There are several different types. There are also muntins which actually seperate different panes of glass. Consider thr the look vs the expense of either. It will change the look of yyour home significantly. First decide the stle you are trying to achieve, then make decisions that will achieve that look. Typically mullions/muntins appear better on big windows. It's a question of what you prefer. Good Luck!

I might consider this configuration

Suggest doing the windows and siding together as they need to be integrated.

I would do 6/6 like it is, or 6/1, or 1/1. Any of these are what these houses originally would have had, and are the most appropriate IMO.

I show the house in charcoal with white windows but different style of mutins than what you presently have. I would make the fascia larger, enlarge the columns, and make a nice walkway leading to the front door perhaps in bricks with brick steps & black railings on both sides. I find that with those changes the front door with 2 sidelights makes the entrance inviting. I also suggest you work on the landscaping for additional curb appeal...