Fire Emblem: Radiant Dawn

1. Your character selection is ok. Some people may tell you to ditch Soren or Rhys because there are Mage Haters in the message boards, but I personally LOVE mages, so keep 'em I say. The only thing I would change is use Rafiel over Reyson, but it doesn't matter too much as long as you don't use Leanne.

2. Actually, yes! That is how I play through every time I play and it works out fine! If you play on Easy, definately. Medium, a little harder but still possible. Hard, no.

3. Give BEXP to chatacters that max stat(s) that level up a lot for that character. Example - If Soren maxes Magic & Resistance, feel free to level him up with BEXP, otherwise use BEXP to give the characters 99xp so whatever action they take on the field they will level up.
BEXP won't go away after Endgames, but you won't be able to use that BEXP again until you are that group.

I hope this answered your questions!

Yeah, I see no reason that couldn't work. The only change I would make personally is to switch one character for a dedicated healer (Mist, Rhys, Elincia, etc.) just in case, but it's hardly a requirement, I just tend to play things cautious.

While it's not impossible to play through the games with just those people, I have to imagine it would go a lot more smoothly if you build up some other characters with them, especially if you're playing on anything other than easy. My main problem with the endgame was that I had far too many powerful characters I wanted to bring into the tower, and every single person I brought in at the beginning ended up at 20/20/20 except for Ena and Sothe (because I mostly just had them hide in the corner, the useless hangers-on that they are). I was playing on Normal, though, so experience points were not hard to come by; I would have had to raise fewer people on Hard mode where they're more scarce.

The only ones that I think should stay amongst the selectable units are Soren and Nephenee. Rolf is better than Shinon due to the fact he shows more promise. Replace Edward with Mia, Nolan with Boyd, and Oscar with Mist. Mist and Boyd with A level support work out really well, especially when armed with the right weapons. I recommend you put Naesala in the team. He's pretty good at dodging attacks. If you're on your second playthrough, I suggest using Pelleas. Pelleas has proven to me that he's capable with the right training. In regards to bexp, use it if you have to. Especially for filling in gaps for the stats that haven't capped yet. That applies to everyone that can fight.

I would consider using either Zihark or Mia instead of Eddie if you are on hard. Admittedly, Eddie has good growths, but he starts at a low level and is difficult to level effectively on higher difficulties. But it can be done, and he is effective with the caladbolg during part 3, so if you want to use him, use him.

I would also use Jill and Haar over the course of the game. Compare them to how Nolan turns out and see how they do. Since flying is useful in endgame (at times), choose who looks best. Oscar is not that good, and is difficult to BEXP abuse because he takes a long time to cap any stats.

I'm pretty sure you can have 2 more slots. I would recommend either Elincia or mist for mounted, 9-move healing. Of course you have enough psychics that it should not matter, but why not? Another great option are the high-level laguz: ranulf, ulki, janaff. Ranulf is probably best since he doesn't have to worry about the crossbow users in part 4-2 whom I remember being fairly numerous. If you get him SS strike - which is not all that hard to accomplish - and a laguz gem, he will do wonders.

For the use of BEXP:
-If a character has no stats capped, you should distribute BEXP when they can w/out leveling them up. (for instance go up to 99 EXP and let them level-up in battle). Don't do this for a character w/ a high level who does not need to "catch up", but it's useful to do this for a character like Soren who is a little low on levels.

-If they have stats capped, subtract the growth for that stat from their total growths. If total growth falls below 3 (300%) you will ideally level them up only w/ BEXP to get higher stat gains. But it's not easy to do that every time, instead do it when you can. BEXP always gives 3 stat points, so the idea is that if the character is likely to get 2 or less, BEXP levels will be better.
serenesforest.net/fe10/char_growth.html
serenesforest.net/fe10/average/index.html

Basically, if you level up a character at high levels (when their good stats have already capped) the stat points will be distributed in stats they don't normally gain points in.

I never use BEXP.It damages the character's usefulness.They wont be as good.Replace BEXP with boss raping.Keep Eddie,keep Nolan,add Leonardo.You probably won't belive me,but he is the best bow user in the game.When Leonardo is third tier,his speed will be super high,his criticals will be just below Eddie's,and his damege and skill are really high.Eddie,when leveled up without BEXP,is really good.Same with Nolan.Give Sothe adept so he can do some damage.Replace Oscar with Elincia and give her nullify.Keep Soren,collect as many long range magic tomes as you can.In the tower,use Soren as long range artillery.If you really want to keep Nephenee,give Nephenee Imbue,because her magic is high.Give Kurhnaga a speed wing and Paragon,since you dont have much time to level up this awesome character.That how I would do it.

That's a really great setup you have there, I'd only replace the two Laguz Royals, Oscar, and Shinon for other units. (I don't like using them in the Tower, as it makes it a cakewalk, I like Astrid alot more than Oscar, and Rolf for me usually turns out a helluvalot better than Shinon. but PEMN.)

As far as BEXP goes, just give it to the units that have generally 5 or so stats capped. And no, it doesn't disapear when you go past an Endgame.

These units here are basically some of the best in the game. (Some people may disagree on some, but they turn out really amazing. 'cept with Astrid and Vika, you gotta do ALOT of Favouritism/Boss Abuse in the chapters they're in before 4-P, or 4-2 for Vika IIRC.)

Nephenee - Wishblade
Nolan - Urvan
Rolf - Double Bow
Soren - Rexcalibur
Jill - Forged Silver Axe
Vika - Beak (SS Rank)
Astrid - Forged Silver Bow
Edward - Vague Katti/Alondite
Mia - Alondite/Vague Katti
Elincia - Amiti/Psychic Staff
And then for the Heron, I added Rafiel w/ Celerity. (Seeing as how I killed off Leanne twice, and Reyson once.)

This is my Endgame team, not including the required units.

Eddie-Alondite
Nolan-Tarvos
Shinon/Rolf-Double Bow (Both are really good, but just use one!)
Jill-Urvan
Mia-Vague Katti
Nephenee-Wishblade
Tanith/Marcia-Forged Silver Lance (Whoever has better stats)
Haar-Forged Silver Axe
Caineghis-SS Rank Fang
Elincia-Amiti
Rafiel-Clerity+boots for 9 Movement!!! :)

Really, if your on Easy, use any units you want. Bexp abuse all of them so they can be good.

On Normal, You can still use any units you want, it just gets harder.

On Hard, I strongly reccommend that you use the following units:

Part 1- Micaiah, Sothe, Nolan, Jill, Eddie/Zihark

Part 2- Elincia, Nephenee, Haar, Maybe Marcia.

Part 3- Ike, Mia, Shinon/Rolf, Titania, Tanith.

Part 4- Sanaki, Kurthnaga, Ena, Tibarn, Caineghis, Nailah, Naesala, and Rafiel as your Heron