Looks like it. But that mostly covers adventure play - and that would be a lot of work to make a game in an area that has been well trodden…
Birthright has 3 different types of play: adventure (standard D&D), battle (war-gaming) and realm (civ-type gather resources and grow). There are quite a lot of differences between 2e and 3e at ‘adventure’ level, a few at ‘battle’ level; at ‘realm’ level 3e has a number of differences although mostly these are to reduce randomness or reflect philosophical or mechanical changes in the ‘adventure’ system.
A lot of gamers seem to have shifted over to 3e, certainly anyone new to the game would be more used to it, and the general mechanic is more consistent than 2e. Given that there are two game systems (the Gorgon’s alliance and birmail) that run on 2e, if you want to do something new I’d suggest 3e (and get beta testers hint hint). Have you seen both systems?
It depends a lot though on what you intend to do with the game you make. For example whether you are building a ‘solo adventure’ for you to have fun with, or if you are building a ‘DM’s helper’ to help in a PnP/PBEM game.
Solo adventure
The Gorgon’s alliance tried to do all three levels of play in BR (with varying success). An adventure level game is like vast numbers of other games on the market, an avatar (the PC) with buddies wanders around a map interacting (fighting, talking) to other beings and objects in the game. A Battle game would let you play out combat between armies without having to roll a million dice. A realm game would let you build up a realm and play against other realms, but might be a bit limited on its own.
DM helper:
Birmail is an example of a DM helper. It handles most of the ‘book-keeping’ for realm play saving the DM time and effort on what many see as a chore.
A game which tracked realm play, handled the bulk of NPC realm actions, but allowed a ‘DM’ to force actions by NPC’s to suit their machinations, make manual updates to NPC’s, holding levels, edit the map to produce an aesthetically pleasing design, etc would be of great help to a 3e GM - with that sort of game adventures and battles could be played on a table-top or on alternate platforms and the results simply updated onto the ‘helper’, if the helper could actually be played at realm level then all the better
Given that you can get various games for adventure play (baldur’s gate, neverwinter nights) and battle play (medieval war) I’d go for a realm level game only, or a realm+battle game to make something different. I’d have thought an adventure-type game would be the hardest to build in any event and the one most likely to be judged by it’s looks rather than the quality of the game itself.
Looks right, but:
The only thing you really need from the set are the BR rules (for bloodlines and ruling realms) and the map. The rules were an add-on to the standard AD&D system and you could use the BRCS without too much trouble, maps can be found in various places on the net.
If you want to know more about the setting you can look on the wiki - it’s got the history, several realm descriptions, etc.
The only real problem with using the BRCS realm level rules with 2e would be in RP collection - in BRCS the system uses skill levels, in 2e it simply said all get RP from province levels, fighters get RP from law, priests from temples, thieves from guilds and wizards from sources. Otherwise although a lot changed from 2e birthright to BRCS you should be fine.