Consider using 2.54mm hole spacing instead of 1.27mm hole spacing. This will allow use of the formed lead components that are often sold as tape/reel or ammo packs. The bulk (1.27mm) can be manually "widened" (in a straight line) whereas the formed lead (2.54mm) is much harder to "narrow".

Also some more unsolicited feedback for the OP:

I would consider flipping the 8255 180 degrees. It's the only IC that is oriented 180 degrees to the other. For consistency it is good to have all the ICs oriented the same way. I have yet to find a board from a Williams (System 11 and later) machine that has mixed orientation. The ICs are always in the same orientation - presumably for consistency. You have already laid out the tracks and connections so it is some work and the work would warrant not wanting to do this. That's a fair argument against it and in that case it's something to consider for your next board design should you do something new.

This is often done by people replacing a single IC at a time and not understanding about the requirements of pin 1 or the notch/dot. Usually EPROMs.

Having said that I've also installed sockets oriented incorrectly as well as IC oriented incorrectly. This usually happens when I'm in a rush or feel pressured and get lazy. I usually line up all the ICs and socket notches in a consistent manner. I scan the notch location for consistency. This scanning is auto-pilot. Having to make an exception for one is where problems can get introduced.

Everything is subject to human error (even when things are built by robot as the programming of the robot is by a human). It's the root cause of every problem you will ever see. Minimizing (if possible) human error is always my number one priority.

I have thought about doing similar things in the past but my desire for consistency is more important than trace routing. I avoid excessive / unnecessary vias as well. In theory every hole in a board is a potential weakness in the fiberglass structure. But I, personally, think that complex trace routing is a price I am willing to pay for reduced risk of human error. That's my opinion. I am sure there are people that will disagree and think that my opinion is an example of human error.

I can only assume this comment is directed at me as I was the one that "created the issue". I was just trying to point out the difference and inconsistency I see between other boards that I have worked with. There is no right or wrong. There is no rule that says everything has to be the same way. Of course you should double and triple check components with orientation before installing. I am glad this board has been made. I had thought about doing this board without the adequate experience to help the community but with this kind of comment I am really happy I did not do this. It is clear to me that trying to help is just "creating issues" so I will stop now. Back to your regularly schedule (uninterrupted) programming.