Not a bad idea. I came from SF3/SF4 myself so i know how it feels to transition. Here are the main differences I've noticed:
-KOF has 4 different types of jumps: hop, hyper hop, normal jump, and super jump. SF generally just has a normal jump, along with a super jump in some games or with specific characters.
-Ground movement is very different from SF in KOF. Instead of dashing forward, your character will run. Walk speed is overall slower in KOF compared to SF so it isn't relied on as much as running or the 4 air mobility options. Both games have backdashes, though, and are used pretty much the same way (except in KOF, backdashes don't have any invincibility so they will lose to meaties).
-The ground/footsies game in SF is more prominent and a little deeper than KOF, due to SF characters generally having more ground normals to work with, faster walk speeds (more so in older SF games), and all jumps being very easy to react to with anti-airs.
-KOF has a lot more universal mechanics, and because of this, is less matchup dependent. SF characters are simply given specific tools to work with, while every KOF character can guard cancel CD for example to get out of pressure. While KOF characters have their own set of tools, every character has 4 jumps, can roll, can guard cancel roll/blowback, and can use HD. All of these mechanics make it hard to get stuck in a situation where you're absolutely screwed, and put all of the characters on a more level playing field than a SF game.
-KOF is a little more execution dependent than SF games. Being able to execute all 4 jumps at will takes a decent amount of getting used to, and longer combos such as HD combos take a little more practice to get down than your average SF bnb.
-KOF is overall faster. Fast enough that some things are difficult to react to, such as Iori's short hop. As such, the game is part reactionary, part preemptive. It's hard to anti air a hop with a DP on reaction, but normals such as standing A are used preemptively to prevent the opponent from hopping in recklessly. I don't see this kind of tactic used nearly as often in SF, as SF is a little more slow and controlled.
-KOF (at least 13) tends to favor the aggressor more than SF does. Blocking for too long will cause you to get your guard broken, and give your opponent a free combo. An anti air dp generally does no more than 150 damage (unless we're talking about Mr. Karate), while an HD combo can do up to 100% off of a jump in. A lot of characters in KOF have more offensive tools to work with than your average SF character (hops for fast high/low mixups and command grabs that lead to combos/resets all in 1 character). So the risk/reward is skewed a little more in favor of the player who is attacking more, but don't get me wrong, KOF still requires very solid defense if you don't want to get opened up quickly when being pressured.
That's about all I can think of for differences at the moment, although I know there is a LOT of ground that I didn't cover.
Characters that are similar in ways to SF characters to me:
-Abel and Clark/Daimon. Abel can roll like a KOF character, and use it to create ambiguous mixups just like Clark. He has an anti air command grab like Daimon, and overall seems more like a KOF grappler than a traditional SF grappler such as Zangief or T Hawk.
-Ryo and Ryu. Ryo almost 100% reminds me of Ryu and shoto characters in SF. He has one of the strongest ground games in KOF 13 with high priority, fast ground normals, and a fireball shield that is difficult to get past. He has a fireball,
a traditional Street Fighter DP, and a move very similar to a SF shoto's tatsu. He also has a parry, so 3rd Strike fans may take a liking to him, although you can't quite use his parry the same way you would parry in 3S.
-Yuri and Akuma. Yuri has Akuma's demon flip, and an air fireball. You can do demon flip mixups with Yuri similar to how you would with Akuma in 3S (canceling demon flips from ground normals), except Yuri's demon flip has stupid good crossup potential compared to Akuma's, and her demon flip throw is less effective outside of combos.
That's all I can think of for now. I know there is a LOT of stuff I didn't go over, but I'll leave the rest up to others. I hope this is a decent start and that it helps anybody who is transitioning from SF to KOF. Feel free to correct me if something doesn't seem right because I don't want to spread misinformation.