This really just sounds like a Knight vs Samurai contest where in the end, the weapons and equipment don't matter, only the individuals skill and creativity. An actual victor could only genuinely be found if you put limitations on the contest, such as no force powers/surge bindings, only bladework. in this situation, I would say that a Radiant would most likely be the victor, since their shardplate would give them greater strength, speed and agility, and their shardblade adds extensive reach to the equation. If you then allowed a Jedi to use the force, only for physical, and mental enhancement(still nothing external), then I would give it to the Jedi, as they are able to use the force to predict incoming blows, and plan around them, similar to using atium from Mistborn, which is nearly(although not entirely) impossible to outplay.
By the time you add all other external powers and surges to the two contestants, it becomes impossible to draw an accurate conclusion, and will be entirely situational.
As for whether or not a lightsaber would be able to directly block a shardblade: yes and no. While it is true that a shardblade can cut through any nonliving matter, and a lightsaber is nonliving matter, this can only be said of the Shardblade's edge, not the entire blade. If a Jedi were to parry a Radiant's stroke, rather than stop it directly, then there will be very little issue, although it would limit your possible reactions to any given attack.
In any case, it would make for a very entertaining confrontation, that I would love to see in a Deathbattle one day.