Offensive characters for beginners?
Kasumi, Hitomi, Hayate, Kokoro off the top of my head. I recommend Hayate because he is the one that requires the most fundamental skills to get wins with and thus by using him you will get a good feel for most aspects of DOA. He has a balanced moveset with quick strikes (although poor string mixup) and ranged combat capability so you will learn to develop footsies and proper spacing habits when using him more so than other beginner characters. He also has a special sidestep with good evasive capabilities but you have to make sure you use it at the right times if you don't want to be punished. He is also highly unsafe so this forces you to play smart and not like a fool. Otherwise you are getting throw punished all day long. His damage output is also really high and he has nice throws. His juggles are braindead easy as well; He only has one difficult one that isn't even necessary because it only does 5 points extra damage than his best combo. Both you and your friend should try Hayate out.
Hitomi would be my second choice. She is fairly safe, has good whiff punishment options and good strings. Her holds also do great damage and her punch parry is good for dealing with high / mid p pressure. She also has a throw that grants frame advantage so you can practice proper pressure techniques with her. Her juggles are also brain-dead easy and usually consist of launch > string. Since she has long strings beginners may be tempted to mash them out but good players will make sure you don't do that and punish you for it.
Kasumi is all out rushdown and is the character with the fastest initial pokes in the game (9 frame jab, 11 frame mid, 12 frame low punch.) Her range is poor and she is highly unsafe. If you choose her you will be learning how to use speed, free canceling and delays to aid your offense because that is key with her. Relying too much on strings will get you thrown and relying on pokes will make it easy for some characters to harass you. Her mixups come mostly from free canceling on a stunned opponent to get high counter throws or launchers. She has parries and does solid damage with her holds. Nothing too high unless its the advanced mid kick hold but her hold damage is solid enough. She has great throws to punish holds with though for a beginner (assuming you are new to fighting games) you are going to need some execution (timing and free canceling) to do the more damaging combos off the throws. The only reason she isn't my first or second choice for beginners is that since she is fast and can get stuns easily most beginners will develop bad habits like mashing out strings and attacking out of massive disadvantage and won't learn concepts of safety and punishment especially due to how terrible this games net-code is. People will argue the same can be said for Hitomi but I've run into more Kasumi players who fight like they have no damn sense than Hitomi players.
Kokoro has the most easy offense out of everybody I listed. She is safe and can open people up easily with her Heichu grab and 6P+K. She has good speed and tools in close and mid range. Her mid range tools allow her to do many things: Approach safely, start her own offense and whiff punish. Her flaws are that she is linear and has some slow launchers so you will have to use strong mixups in order to force your opponent to hold incorrectly so you can capitalize off of them which isn't difficult to do because she has some of the best mixups in the game. Her strings can easily push her through the threshold and bait holds. Combine that with free cancel mixups and you have an offensive beast. Kokoro requires just a bit more execution than the others because you need to free cancel in most of her juggles to maximize your damage output. It's nothing difficult at all though.