Everyone can be good, I imagine, if you level them enough and give them decent gear, but I'm mostly concerned about her children and whatnot. I haven't been using her, but I'm early enough and my team is powerful enough that I can plug her in. Seems like she can only marry the created avatar character and only support link with one other person I don't have yet. Seems super limited. I'm getting to the point where I need to figure out who my main character will marry and which children are the best or whatever.

Not super in to the actual character stories (I mean I am to a degree, but lack of Master Seals have prevented me from getting Lissa and Maribelle to the point where they can damage and heal, which makes support linking them with the avatar character tough since he rarely take damage), but mostly I've been pairing people with those who cover weaknesses or help add range to attacks. So Vaike I paired with Miriel, Virion with Sully, Chrom with Sumia, and currently Lon'qu with the dark mage lady. My guy is a mage (well Mastered Tactician, but I mostly use tomes), but the only female melee characters I have are Panne (who I've been pairing with Donnel, along with the dragon girl since she can attack from range) and Anna. I guess there's Olivia as well, but she seems easily breakable and not all that strong. I just got her. I'm at B with Lissa, the dragon girl, Maribelle, Panne, and a couple of dudes, but have been hesitant to pull the trigger.

It seems, since she can attack and heal, that Anna is incredibly versatile, but realistically so is my main character. So does Anna get "Donnel good" if I level her up enough/advance her and is her child fantastic, or does the lack of support with anyone else ruin her? I know there are already "who did you marry threads" so I won't bother asking that, but I guess I need to decide pretty soon.

Do Panne and the dragon girl top off as well? Like they can't be Master sealed, and if I Secondary Seal them it looks like they can't use the dragonstone or the beaststones, which are pretty strong. Not sure if I should stop taking them in to battle because I feel like those are pretty strong weapons, but if they won't get EXP after hitting 20 it seems like it doesn't matter.

Not sure about Anna, but concerning Panne, I second sealed her to thief, then up to Assassin, and the strength and Speed/Skill buffs she and Lon'qu (Swordmaster) give to each other are pretty insane. They've been in my team since I got them, rarely get touched in battle, and haven't capped off yet. I'd say she's a pretty good investment, and if you want to get her back to her base Taguel class, she restarts at level one. So there's always room for more leveling there.

Anna doesn't have her own child. The only child she can have is the MC's child. If you're having trouble making a decision, it might be worth noting that the MC's child is the only one that can inherit Taguel or Manakete special classes.

As far as Anna's strength is concerned, thanks to Second Seals, end-game stats are almost irrelevant. At max level every character is going to be within 1 or 2 points of each other. Anna is generally going to be lower in Str/Def and generally higher in Mag/Lck/Res than other characters, but only barely so. As far as using her throughout the story is concerned, she's become one of my go-to crutches to cheese my way through shitty situations. Thanks to her high Spd, Mag, and great avoid stat (thanks, in part, to her lvl 5 skill), I can throw a Levin sword on her in almost any mission and just let her run off and solo half the map. Of course Levin swords aren't easy to come-by so I try to use them sparingly, and she fares almost as well with a regular iron/steel/silver sword as long as all her enemies are fighting at melee range.

It's true that she's significantly more limited when it comes to pairing, but all it takes is one. I'm at chapter 17 right now and, as someone who uses every character in order to keep them evenly leveled, Anna has been one of my most effective units.

Thanks to both of you for the advice.

Figured that Anna could only have the MC's kid, but didn't know his (I'm playing a dude this time, girl on my next run through probably) kid was the only one that could take on the Manakete class. I do like that the Manakete can attack from both close and range (like my MC can right now) so that may be worth pursuing just for the benefits it brings. Not that it matters, I've been switching out characters and aside from like Ricken, Stahl, the other pegasus knight lady, and the dancer no one is really low level.

Might start leveling the dancer, but she's so weak at base that it doesn't seem worth the time just to let a pair of characters attack twice.

The flexibility dance offers you is pretty great, and it's always equally effective no matter what level Olivia is so the only downside to bringing her along when she's weak is the need to protect her. If you wanted to be extra cheap about it you could go on a mission with an immobile boss, kill everyone else, then just let her dance over and over again to powerlevel her.

Plus she can have a child so you're going to want to get her synergy up with another character at some point.

I can't believe I never thought of that.