Is Bedevire worth leveling at NP 1?

Not if you have sumanai. Even without his strengthenings sumanai is quite a tanks saber with his strengthenings he gets the damage caught up.

As to Bedivere, at np4 or np5 he's worth using. If you can afford it I'd say to level him. His real unsung advantage is that he needs 0 investment in his talents so you can just play him as a 1/1/1 without too much detriment and maybe level him to np5 when there's a rateup again. His np is really good, especially with NPBBb.