I suppose the reason your asking is you're aware of the obvious short comings of the .357 as a rifle cartridge.
To accurately assess weather or not your decision is foolish (your words not mine), I would wonder what it is you plan on, or don't plan on shooting, and at what distance. Or... What distance would you sight the gun in at and what type of sights would you want on this lever gun?
Although both weapons can use the same cartridge it's very unlikely that they both will deliver good accuracy with the same load...so your back to 2 different types of ammunition even though it's the same case and caliber.
Having briefly studied the ballistics and trajectory of this cartridge through a rifle, I was surprised to see it's more effective at 100 yards than I thought it would be. You get about approximately double the kinetic energy when you shoot a properly loaded .357 round through a rifle, than you would the same round through a pistol....depending on bullet weight.
Having said that, it's still a very limited cartridge when compared to what most of us would choose for a rifle.
But then again, it depends on your use and your expectations. If you think you might take a shot at a deer at ranges over 100 yards, it's not a good choice in my opinion as that round starts to drop dramatically at around 110 to 120 yds.
I personally would not buy a rifle on the basis that you are, that is the convenience of having to carry one type of ammo. Rather I think I would consider what my needs were, select a cartridge base on that, and the type of action and rifle available.
It occurs to me that a little more range might be desirable, since you are going to carry a carbine anyway.
I, like a lot of us felt the need for a lever gun and I looked at ballistics first, then selected a cartridge based on my needs and expectations. I went with a manufacturer who made lever guns primarily.
I ended up with a Marlin chambered .444.
I am not recommending this for you. As I mentioned, I don't know what your needs and expectations are. Perhaps you should look at this next purchase as an opportunity to expand your range and your collection. Remember, this cartridge was developed over 75 years ago as a handgun cartridge.
