This thread has been catching my eye ever since it started 3wks ago, but I've been reticent to respond.
I started shooting a 44mag revolver when I was 7, carried one on my hip around the ranch most days throughout middle school and high school, and the Marlin 1894 in .44mag has been a tradition of sorts in my family for 3 generations - every man in our family has one, and we all used to have the same ammo available in the farm trucks, barns, ranch house, etc. I also shot Cowboy Action for a number of years, pretty heavily for about 5yrs, then off and on for about 5yrs after that as work took me elsewhere.
As I read the thread title - "Would it be foolish to to pair a .44 spl only revolver with a .44 mag rifle?" - the only thought I have is this: "does it make sense, really, to pair a revolver with a leveraction rifle?"
If you have a context for which it does, such as working on our ranch where 44mag revolvers and rifles were standard, or shooting cowboy action, then great. Matching up makes SOME sense. Otherwise, it's non-sequitur to ask the question whether it makes sense to NOT match up, because it doesn't make sense TO match up either for most people.
I appreciate a lot of reloaders want to produce one load and have many firearms which will use it, and for those guys, sure, why not? For handloaders who tailor their rifle load to their rifle and their revolver load to their revolver, no, it doesn't make sense to match up. When I was CAS/SASS shooting, I used nickel plated brass for my revolver loads which and yellow brass for my rifle loads, so I could keep the two straight. I didn't even shoot the same bullet between rifle and pistol - 240's in the rifle and 180's in the revolvers.
The history of the frontier and the old west is always interesting, but when it comes to a modern age reloader and shooter selecting their firearms, what the TV Western's lied about for firearms prevalence and applications just don't apply.
Ultimately, you have to answer the question for yourself - if it gives you heartburn to have 2 sets of brass or to not be able to share ammo, then don't get firearms which use different ammo. The levergun should feed .44spcls, but do you really want to castrate your 44mag rifle by limiting it to specials? I wouldn't, but you might be ok with that.
Personally, I don't ever worry about carrying the same ammo. It's just not pertinent in 2017. I almost ALWAYS carry a side arm in the field, often two, since I'll have my EDC Ruger LCP in tow as well, so I might have a 44mag and a 300win mag, or a 357 revolver and a 223 AR, or a 357/44mag revolver and a 243win... Never ever made sense to me to have the same ammo in both - one tool is for short ranges, one for long.