I'm looking at getting a Leupold VX-1 2x-7 scope to put on a Marlin 1895 SBL.   The only silver one I've found is a used muzzleloader/shotgun model, which has parallax fixed at 75 yards.   I did some research and THINK this may be okay, but I'd like to get some more information before I pick up the scope.    Anyone have any experience with that model?   I don't have any set range distance that I plan on shooting, but don't want to limit myself too much.    

Any help would be greatly appreciated.

I think it should be alright if not send it to Leupold and explain what you need and they will reset the parallax. I know if it was on my rifle it would be on 2X most of the time.

The other model I was looking at was a Leupold fixed 2.5x scope.  Do you think that’d be a better choice?

You could make it work but personally I'd choose a different scope.  Even a .45-70 can be stretched out to fair distance and you never know when you may want to practice throwing big chunks of lead several hundred yards.  Skip the optics designed specifically for short distance guns and get one that suits your caliber and needs.

I have one on an AR (not the scout scope version) and love it. I need to get another for the .44 I have on the way. These guys make a slick mount for it.
https://ashleyperformance.com/products/leveractionscopemount?variant=28388793859

Seems my 1x4 pig plex works fine out to almost 300 yards with the .356 win. I don’t think 7X is enough power to get into parallax distortion. But if you’re worried and think you need a bit more range. Send it back and have them add a reticle with some hash marks. I worked up some flex tip loads but it’s been so wet I haven’t mowed the range.

Parallax is independent of magnification.  It is easier to see at higher magnification due to the smaller field of view.  It is also an angular error and thus easier to see when shooting at longer range targets.
A reticle cannot eliminate parallax.  

The only way to eliminate parallax is consistency - either adjust it away every shot or ensure your eye is centered on the optical axis for every shot.  

Most scopes below a few hundred $ have fixed parallax, 100yds is the most common distance.  
With basic marksmanship skill parallax errors are lost in the noise.  If your parallax is multiples off from the range you're shooting at and you have poor technique (ie. using a 100yd parallax with poor technique while shooting at 500yds) then anything can happen.

Shooting 45-70 elevation errors are a far larger source of error than parallax is.  Shooting leverevolution 45-70 zero'd at 100yds you get 7 inches of drop at just 150yds.  At 200yds you get 20 inches(10moa) of drop!  

Leupold will change reticles?

They did on my MKAR 1x4 with a custom 60gr nbt load. I don’t know on the cheaper scopes.

True the error does increase in range and in magnification. That’s why most optics under 10X are fixed parallax. Now most air gun optics also use parallax as a range function because at the higher magnification ranges the reticle distortion occurs. Which equals a pretty good short range range finding technique.

Me personally I can’t see adding the weight of a fully parallax adjustable optic to the .45/70. If you have an old Leupold 3-9 extended focus range optic it would be a good choice but I would rather mount it on a really accurate .22 rimfire.

Same one I have on my Beowulf.  The LPVO's are what I was suggesting although I should have been more clear about it.  They are about perfect for "thumper" caliber rifles in my opinion.  

My only issue with the PigPlex reticle is that it's overly thick.  I wish they had made the center cross hairs thinner.  Other than that it's an awesome optic.  I'm a big fan of the auto on/off "FireDot".

Yeah I complain about the thick reticle while on the bench. But after hunting with them for a couple of years it has really grown on me. It’s not like critters have a bullseye your worried about covering up. If anything the only worry I have is it covering a twig. I really thought it was going to be a hindrance on all black hogs, but I was surprised by how the dark cross hair circle allowed you to instinctively aim on a moving target. Redfield has a close version with finer cross and circle and in the dense timber on 4X I sometimes loose it. Just my experience.

Late to the thread.  Sorry.  Those 2-7x Leupold scopes have user adjustable fixed parallax.  Yes, user adjustable.  Simply unscrew the front of tbe objective bell.  Its just a cover.  Inside is a slotted ring that holds the lens,  it screws in and out to adjust parallax.  That adjustment setting is the only difference between rimfire, centerfire and muzzle loading versions.  Adjusting this does not break any internal seals.