Im not sure about the geometry but with changing things like forks length it can weaken the frame by changing the angle. Im sure someone else can enlighten you further just a little heads up sharing what I know.
I can help on this I think.
Changing your forks length
does not weaken your frame. However, if you are using a longer fork length than what the frame is designed for, obviously the headtube angle decreases due to a longer axle to crown length. This results in more stress being placed just behind the headtube whilst riding, potentially leading to a breakage.
If you want to avoid this, ride a hardtail that is long-travel specific, or at the least long-travel compliant (by this I mean has a range of travel tolerances, such as the Jamis Komodo).
I am currently riding a Jamis Komodo with Lyriks up the front - regularly changing the travel from 115-160mm. The Komodo is designed for 100-160mm travel at the front, therefore I get away with it and do not risk snapping anything. Whereas if I was to put these travel forks on say, an STP, the slackened headtube angle as a result of a longer axle to crown length
will put excessive stress on the headtube, and likely snap.
Hope that helps
They're all so young!