Without Utopia: You can reserach both Geneseed Purification and Psionic Armies tech the same way you can now.
With Utopia: Progressing past the 1st Tech (Psionic Theory) requires the Ascension Perk. Geneseed Purification in particular needs teh 1st Tier of Biological Ascension.
That is one of the bigget issues. Finding out the parts that are in the lore but not that Important.
Another example actually are the Space Marines/Gene Warrior armies. While they are a full blown "Faction" by the games and the Army Rulebooks, thier numbers are highly limited. Official Lore rule States: "There can not be more then 1000 Space Marines per Chapter".
1000 marines is a nominal, and nicely rounded maximum. However, a chapter can easily be overstrength - The organisation slate allows for 100 marines per company, **plus specialists** who aren't numbered in a standard squad or company (chaplains, techmarines, and apothecaries are a separate part of the organisation slate, and the command squads for each company may or may not (depending on the chapter) also be one of the regular 10 squads.
Then we have chapters that don't follow the Codex Astartes in a meaningful fashion :
The Space Wolves nearest equivalent to a Company is a highly variable force - but could potentially be equivalent to 14 squads (6 tactical equivalent, 3 devastator equivalent, 3 assault equivalent, 2 command squad equivalents), and there are 12 Great Companies (or whatever wolfish name they've added *this* time - I think they were on "Great Pack" last I saw??).
Then we have the Black Templars - divided between several Crusades, each of which seems suspiciously strongly manned considering the number of them that are going at any one time.
All in all, saying a Space Marine Chapter has " not more than 1000 Space Marines" is describing the ideal state of affairs, and not the practical reality...
Even the Ultramarines have found themselves in a situation where they've got full (nominal strength) companies... and the Scouts they've been training in anticipation of casualties don't have a space in the ranks to move into, because those casualties didn't happen. They can't just make a new chapter - that has to be approved by a "proper" founding being authorised. So what they *probably* do is let the companies fill out to 6 tactical, 3 assault, 3 devastator, and 2 command squads (one for the captain, one for the chaplain), and slacken off on recruiting Scouts. Of course, an alternative with the Ultramarines is to pass the excess Scouts to their gene-brothers in their subsequent Founding Chapters. Another alternative would be to make additional "grey" reserve companies to hold the excess, and to act as a pool for reserves.
Something like the Space Wolves would just shrug, and add them into the line strength though.