This is a difficult thing.
- For a given bike or e-bike, the fork and the frame form the frameset of given geometry
- It is not easy to find the replacement fork matching the fork length; headset; the hub of the existing front wheel
- The suspension fork is good for the frame integrity. Unsuspended bike experiences more stress in the frame, which may lead to frame cracking, especially on a heavy e-bike.
I do not recommend doing that. It took Specialized only a year (2017-2018) to realize using a rigid fork on a MY2017 Vado 5.0 was a mistake, and they replaced that model with suspension fork frameset on all Vado models since.
I was riding an unsuspended MY2017 Vado 5.0 for 3 years or over 13,000 km until the frame cracked. Once the frameset was replaced with the one of 6.0 (with suspension fork), my rides have become a pleasure.
I understand you are after reducing your Vado weight. Shouldn't you have bought a Vado SL 5.0 instead?
Just a question!
Cannot help you with that as my e-bikes run on 700c wheels and I have no experience with 27.5" tyres of the properties you are asking for.