Firstly, why make your own engine when you have no programmers(as far as I can tell; you may want to reconsider the title 'engineer' in favor of 'producer' considering that you seem to have the final say on all aspects of the project)?
That's precisely my point in trying to find programmers... and yet some jealous Croatian (at least, I assume he's jealous given his allegedly less-than-reasonable attitude towards me, though I'll admit he did have a point about calling myself an "engineer") is trying to tell me I can't hope to recruit programmers to work on my engine unless I actually
create a working engine from scratch.
Secondly, why make two games? Your features list doesn't include multiplayer functionality(which I do not recommend adding on until you're nearly finished with the project anyhow), and developing two games in tandem is(as I mentioned in your general discussion thread about paired games) a waste of time anyhow since you aren't beholden to any sales on a non-profit fangame. You're adding an extra step to your design process for no reason whatsoever.
Actually, multiplayer functionality for paired games should, in my humble opinion, go without saying anyway. Plus, a Red version remake wouldn't be complete, again in my humble opinion, without a Green/Blue version counterpart.
Why add a whole new region to your game? You've already promised almost 2 games' worth of content with just Kanto and the Sevii Islands, not to mention the additional challenge of balancing late-game Pokemon for Albion.
In addition to making sure all 18 Gen VI types are represented by official Pokémon Gyms, I'm also intending it to help make sure as many of the 721 as possible can fit (including exclusives between the pair itself), which brings us to...
Finally, why commit to including all 721+ Pokemon? Even as we speak we've got the rumors circulating about Mega Zygarde and Jim Henson's Zygarde Babies that new blobby thing, and knowing the development time of Pokemon fangames of the two-region scope(I consider Sevii Islands to be effectively one region due to the discrete nature of the separate islands), it's fairly safe to say that another generation of Pokemon will appear long before you finish the project. You'll have to balance those Pokemon in consideration with your gameplay in addition to the ~218 available in FireRed/LeafGreen. Additionally, when you talk about gating Pokemon availability in the same way that the original games did, you'll have to commit to a plan to keep those additional Pokemon worth catching in the late game. Unless your goal was to complete the pokedex(and there are scant few who will do so in a fangame), what motivation does a player have to change up their regular battling team in your late game?
Well, I have to include at least
some Pokémon from all six generations in R3D and Green 3D, kind of like FR/LG did (except that game had only three generations to deal with). There will also be three Pokédexes: the Kanto Pokédex (developed by Professor Oak), the New Pokédex (developed by Professor Elm), and the National Pokédex (a joint effort between Professors Oak and Birch). Each Dex will be acquired at progressive stages in the game.
If you're really this eager to make a new engine, why not also just make an entire new game that you can then sell? And you can design the engine with pokemon in mind, so that once you're done with the project, you can more easily make a pokemon fan game if you're still interested.
Also, if you want to make a 3d game engine, you should probably learn how to make one. People are more likely to come help you out if you're already doing something.
As for you, you're starting to sound like the aforementioned Croatian, only somewhat more helpful. Come to think, there's spots open for engine personnel if anyone's interested in assisting me with building Project Vulpix (the name of the engine, like I said earlier).