When I saw it was your first home and your trying to take on that big a job that scares me.
Any older home like that I always suggest starting at the roof. Make sure there's fairly new shingles, inspect in the attic for any leaks, and fix that first. If it leaks anything you do below will fail.
Then we inspect the foundation and supports under the floors. If this is not right then cracks will show up and door ways will never be level. 90% of the older homes we've worked on did not have enough piers, insect of fungus damage. If it's over a crawl space then you need to add a 6 mil. black plastic vaper barrier on the bare ground.
Then check to make sure there's newer style windows and add replacement windows if there the older style.
Check out the wiring and plumbing. If it's steel, Quest, or you can see lots or repair patches, it would be best to redo it all with Pex using a central manifold.
Check the condition of the heating and A/C system. If it's good then have someone relocate any duct work that's going to be in the way of the redesign.
If walls are to be removed or just move we figure out if there supporting walls fiirst. If they are then supports under the floors and above needs to be done.
Have the septic tank pumped and inspected.
If all of this is not done first and brought up to snuff, the fluff stuff you do to the inside will be useless, your money will be gone, and the house will be unsaleable.
Then and only then do we start gutting.
I also would have tryed to leave the curved archways. A boxy opening cheapens up the look.