mandoman, maybe this will help you out ...
If I'am just shooting my 45/70 brass in one gun only do I need to full length resize?
No. Just insure the neck tension is between 0.001 to 0.002. This can be done with a special neck sizing die. I just reset my resizer/decapper die (pin removed) to put the proper diameter on the case neck ... AFTER I have finger seated the bullet
does anyone make a 45/70 carbide die ?
No, and the reason is because the 45-70 is really not a straight sided case. It has a slight taper towards the mouth
If I have to lube the brass is there a special lube for black powder cartridges in case some gets inside the case ?
Any commercial lanolin based case lube will do the trick (most of the commercials are lanolin based). I use lanolin as part of my bullet lube ingredients, so I just mix lanolin to Isopropyl Rubbing Alcohol, 99% ... 40%:60%
Enjoy the Smoke and Happy Shooting