No. The model 25 came in various calibres - we'll assume yours is chambered in either .222 or .223 Remington. The 5.56 does not match dimensions with the .222, so if that's yours, it won't even chamber.
The 5.56 does match dimensions with the .223 Remington. However, there are differences in neck angles which can cause improper headspacing if a 5.56 is run through a dedicated .223 chamber, as well as chamber pressures which may exceed what a .223 rifle is intended to cope with.
lighter bullet and more ammo can be carried as opposed to the 30/06 or 308
No. The savage has its own chamber design. Use only what is stamped on the barrel.
If your barrel is marked .300 Savage then you can shoot .300 Savage ammunition by any manufacturer. I do not know of a "300 Savage Winchester Magnum".
yes, but better to use standard ammo. +P ammo shakes the pistol a lot.
Best would depend on intended use. Federal makes good 30-06 ammo. Soft point for hunting, FMJ for target use.
No
Take it to a gunsmith for verification.
Yes I believe that the Savage model 110E and the regular model 110 will share the same scope Mounts.
S&W has never made a firearm with the model number of 94
.45 Long Colt.
No - they are very different cartridges.
The marlin model 781 was chambered for the .22 long rifle.