Laying a flagstone path does sound like a lot more fun than fighting with your contractor. Curve vs. straight: this is a design issue that I think needs more context. If your taste doesn't guide you strongly in either direction, you could run this by the landscape design forum (with a photo or a good description of the layout), but be prepared there to hear about any aspect of your house and landscape and not just the path. Tiers vs. slope: sounds like a no-brainer to me; obviously you need to keep the base material in place. Tiers. But you contradict yourself when you say you don't mind flagstone jutting into the grass. Unless you make sort of a "landing" that is flat between the two tiers where you can use that style, you can't do both. And the two types of side don't really mix and match either; the unfinished side would look like you'd forgotten to put the edging in. At best you could do a sequence of pie-piece-shaped sections where the curved edge is contained and forms a step while the sides merge into the slope... might be a bit much though! I'm not qualified to advise on base material. Suffice it to say we just put a concrete paver patio on just sand rather than on sand and crushed rock... (it's not gravel that's used for the base, but rock that has sharper angles and more variety in piece size). There are lots of good books and websites showing how to lay flagstone, and I'd encourage lots of reading. They often showcase nice design ideas too.

The planks stink when first taken out of box, I think it is the tacky stuff on edges that helps seal the edges. Also, many were really dirty from the wax on top. Many actually needed buffing before install. I did not bother to clean many, except the really really dirty ones. After install I buffed floor with microfiber type mop thingy. The floors are med gloss. The planks are about 3'long by 7"wide. This made install much faster than last house I did. The sticky stuff on edges looks noticable when first installed but after wiping a few times I don't really notice it. There are no beveled edges on the planks. There are some like that but with kids and dogs I figured claws and such would not be good so I made sure we picked unbeveled edges. One thing I really like is the dirt not showing. My before pic shows original laminate. It always looked dirty because of the color. Once I cleaned area with a toothbrush and it was dirty a few days later. We had lots of yard construction for a year and I just decided to not mop for that year, it was not worth it. Now I just sweep and swiffer mop and it looks beautiful every day. The grooves may have dirt like old floor did but at least it does not look dirty. Because original floor was laminate I knew what to expect feel wise. The dining living room does feel a little hallow but that is just because I was used to the carpet before. But the floor where I already had laminate feels just like before. Some say they only like feel of real wood but it is no biggy to me. My main thing was that if something happened and floor needed replacing, it would only cost a few bucks. Real wood would be costly to repair or replace. Another feature of laminate is that if for some reason I would have to sell some day, I could offer to change the flooring to fit buyers desires and it would not cost much to do so. This would make house more desireable to buyers. In the meantime, I love it.

Back when home building ( 1920 ) made some sense in the four season climates, you had an air lock, a vestibule. with a second entry door, and it was many times glass. It's purpose wasn't to protect your flooring it was to protect the inefficient, less even heat and save you from a blast of icy cold air. The floor was brick.......tile, slate. It was a contained space. We no longer have that nice little contained space. If we did? We'd not use it. Neighbors don't knock on front doors when out for a walk anymore. Folks like Beth above? Common for it not even to get opened! We go in and out of garages attached to the house. In wide open spaces as today, where a "foyer" is in name only, that? ONE surface please? Wood and a rug solve the rain, snow dirt.........and ........ the tile just breaks the space, and makes the rug harder to find. So you can COVER it. Kinda dumb in my book : ) Like the loss of air lock vestibules.

There are only so many choices. There is no magic answer that doesn't cost more than you will get as a return. You are selling in less than a year and really don't want to spend any more than absolutely necessary without impacting the value of your home. I would replace the two transition strips that are trip hazards to a sloped transition rather than a square transition. The trip hazard from your current set up will be noted on inspection and you don't want to draw any additional attention to this mistake. Then I would paint the tile, grout and transition strips the same color as your walls or very close to the color of your walls. The color is already repeated on the walls so no need to repeat. I am not big on painting floor tiles, but it is done by DIYers every day and on HGTV often enough to make it a popular answer. It does last long enough to make many people happy, making it a perfectly fine answer for resale. Here is a blog on 6 month after painting. Floors still look great except in the shower where it has some peeling. Your application is not in a shower. I think you should be good for a couple of years. https://www.housemixblog.com/2020/10/14/my-nitpicky-6-month-painted-tile-update/ You should be able to do this yourself or maybe hire a local handyman to change the transition strips for you if you are not comfortable with doing that part. Painting is something you will most likely need to do yourself, but may be able to get a handyman to do. My guess is that no flooring contractor would be willing to paint the tile.