First off, welcome to the scene. Now let me try to answer your questions:
As far as melty blood goes, the closest to Ryu you're going to get is Tohno in any moon. C is the simplest one though, but any form of him is good.
As for learning the game, pick a main for the both of you. It's fine to have alts and the like, but mains are essential to the learning process, make sure most of your time is dedicated to one character when you're first starting out. As to how to learn or pick the characters, japanese match videos located here are usually a good choice:
http://www.youtube.com/user/MeltyBreadWhen you choose your characters, learn their basic beginner BnBs. There should be combos around on the main character boards or on youtube. If not, ask in the respective character boards or visit #mbaa on the mizuumi IRC channel. Once you learn the BnBs and get them down to a pretty much 75% success rate, you're ready to start playing the game with your friend, assuming he does the same.
Once you both start playing, you're going to run into issues where you both don't understand what is going on or how to hit each other-- this is natural, you're both new and pressure and neutral will be obscure concepts to you. The best way to get around this would be watching match videos of your respective characters and studying them, or asking good players simple questions like "what should I do here?" or "What's my answer to xxxx?" Simple questions like these are usually answered properly and quickly, but general questions like "How do I hit my opponent?" will most likely go ignored since it's a very broad concept and rather detailed and opinionated. In short, watch jp match videos of top players of your respective characters, and ask questions in threads or irc for simple concepts you don't understand.
I'm personally doing a series of live streaming sessions dedicated to newer players of melty blood-- they assume you have some fighting experience, so if these are too fast for you that's alright for now, but I suggest you check them out sometime in the near future, they are hosted every friday. It's located here:
http://www.meltybread.com/forums/kohaku%27s-video-room/mbaacc-analysis-live-streaming-sessions-redux!/If you're both really new to fighting games in general and don't get things like number notation and why you should be blocking among other things, I recommend these series of videos from Xie:
www.youtube.com/user/XiePlusThese series of videos are long and there are many of them, but if you are very new they are worth a watch. While they're centered around BB, many of the earlier episodes hit very key fighting game fundamentals straight from the get-go.
As for which controller is best for you, Stick is generally the most rewarding and easiest to play fighting games with once you get good at using it--- fighting games are designed around them, and they are catered to in new button schemes and the like. This doesn't mean the other controllers such as keyboard and pad are useless, just less optimal and will be harder to use in higher level play due to certain techniques and movements not being catered to them and instead being catered to fighting sticks. Also 360 pads are garbage for fighting games so if you have a stick please use that instead lol
Phew! That was a long wall of text, but I hope it can help you out. Hope you stay around and i'll forward to seeing you in the future
P.S.: While netplay isn't exactly the most competitive and most solidthing avalible, it can be useful in learning how to play against certain characters and players as long as the connection is decent and you have a fair idea about fighting game fundamentals.