Most Nikkor glass is so common and readily available on the market that I could not see an AI conversion as being particularly deleterious to its price. In fact usually the opposite - non AI lenses (at least the common focal lengths and speeds) always seem to attract considerably less $ on eBay etc.
There may be a few rarities where AI conversion might be damaging to price but even then only if they are in top notch (collector) condition. Even here many were factory converted back in the day by swapping out the base ring for the new AI compliant one. And I would not really expect them to attract less $ given their factory "fresh" state.
Just one appeal. Please - please make sure you know your way around hand tools before tackling the task yourself. It is by no means a difficult job. As working on lenses go it is easy - in fact the lens disassembly and reassembly is sometimes more tricky than actually cutting the AI notch so long as you know how to measure, mark up the cut then execute it. I find it a bit distressing when a rough job is done because someone does not know how to use a needle file to neatly cut the required notch in the lens. An AI conversion like that likely would attract less money when sold.
Having said that, the above is only relevant if you propose to use the lenses on certain Nikon bodies. If for example you propose to use them with adapter on a mirrorless camera, save yourself the time and trouble. And have the pleasure of knowing the lens is still in original condition when you pass it on.