The issue with Rhode discovering a way in is easy to explain. Its the most common of writing tropes. She simply found an easier way in. The hero always does it the roundabout most difficult way possible. In fact there are plenty of pop culture reference where the hero goes through this arduous quest and the "other guy" simply says "why didn't you just use the backdoor?"
The bellegar issue, is really a non-issue. You can write it off as he's crazy. That's the explanation that the game gives you over-and-over again. But what I did find odd is how he attempts to thwart you only after you've found certain items and not continuously as his powers would allow. It makes sense from a gameplay perspective but not a rational one. But of course, he's crazy. So there you have it.
If you didn't make this choice in the game here's a real spoiler:
You can choose to side with Berhlihn and ignore Bellegar. This actually presents you with a more challenging final battle if you choose him. Now you have to battle both Berhlihn and Ygerna. Unfortunately, he doesn't put up much of a fight. Does that mean you're more powerful than him? If so, why do we even need him or Bellegar. Just go in yourself and lay down some butt whoop.
One thing I did forget is: why can't you leave and fly around? Yes, the guards are oblivious to the fact you can teleport out of the city, so you can ignore them. You have a Dragon Stone. And your runners seem to be able to find resources from the magical land of Infinite Storage Locker. Bellegar can teleport you, so teleporting obviously works. You should be able to fly outside and squeeze in some dragon action that some forum members thought was missing. Perhaps your tower also has a magical force field that prevents you from flying out from it. And if you take it one step farther, why can't we use the front door of the tower. Its like the elevator has been locked down for our protection. But I think this has already been addressed by Larian as not having the resources to flesh out a zone outside of Aleroth.
ADDED:
Grimm is probably a bug. I don't remember clearly, but I think you only get Grimm talk to him. Its one of the easiest ways to tell you're now playing FoV. There are multiple bits of player data that don't transition over to FoV. If you manually sort your inventory like I do, FoV rearranges your inventory. Certain tower flags are reset, such as first encounter dialogs with NPCs, etc. Most of this I believe was to ensure FoV could be played as a standalone. Personally, I think Larian should have dropped the standalone playback for FoV and rewarded people who purchased ED + FoV a bonus by making FoV a DLC patch that converts ED to DKS. That would have allowed them cut development time on standalone and put more time into refining the game.
