The first 2 are really based on what you need, a physical sweeper or a special sweeper. In physical sweeping Staraptor is superior but in Special Sweeping Togekiss is much better.
However if you are looking stat-wise then Togekiss is by far much better as it has a base 540 stat whiles Staraptor only has a base 475 stat. HoweverTogekiss is usually a defensive Pokemon that benefits from a high special attack whiles Staraptor is a fast and powerful Pokemon so for in-game I would recommend Staraptor
I would say that Empoleon is by far better then Floatzel in every single way and not just because it is my favourite Pokemon. Floatzel is fast and has good offensive capabilities however it's frailness can be used against it very hard even in-game. Sure Empoleon is weak to ground and electric but his Grass type weakness has been shrugged of. It has a great movepool and can learn all the HM-moes barring fly. So for more utility I would say Empoleon is better
Infernape is the best fire type in-game mainly because it is one of the few that actually works well. Rapidash isn't that good however I perfectly used one in Diamond and it worked just fine. However if you want more reliability and a Pokemon with a better move pool, more attack, special attack and speed, Infernape is without doubt the fire type you would want
Roserade and Torterra both exhibit different roles whereas Torterra is a tank or a physical attacker whiles Roserade is a supporter or a special sweeper. I would personally recommend Roserade as it can cover much more. Unlike most grass types it isn't weak to bug and poison which grants it some nice coverage
Luxray is better then Raichu in every single way I can put it barring speed. it has a higher special attack and attack stat. It also has a much wider movepool then Raichu. Even a Pikachu holding a light ball is better then Raichu.
hmmm...the last one is a little harder seeing as they both share the same roles, however Steelix wins as his defense and HP is not to be compared to Golem's. It is weak to fire but is neutral to other things like grass which Golem doesn't take well at all. It's Attack stat is not bad at all and its' special defense is just ok. For more utility and better coverage I would say Steelix is better