I would ask that you delete your drawings. Why? Because another student could come along and borrow them, make minor changes then submit them as their own drawings thus saving hours of labor. You do all the work and they get the credit. Not kosher at all. Follow me?
Addendum: Looks like someone has already done exactly that. Again, take your drawings down. There are plenty of image files (not CAD files for students) to reference. Thank you.
The OP seems to have exited the conversation, but just for others with the same inquiry.
As I have mentioned, this is mostly an issue with your PDF editor, the instructions for using the OCR should be in Foxit Help.
If this is something you need to do going forward without any effort, you need to use TTF.
As most of us use Microsoft Office products I switched from using AutoCAD's Swiss Lt BT TrueType font to ArialNarrow.ttf like SLW210 suggested as it's horizontally compressed to take up less space while being even more easily readable.
While hindsight doesn't fix your immediate problem finding a font that doesn't cause issues with your PDF software before you need to output one to PDF again would solve your issues in the future. I've struggled with the same issue even with the full paid version of Adobe with drawings by others usually because of SHX text with various width factors. Never do that with a DWG you want to output to PDF unless you don't want anyone to convert that text back again.
In PDF-XChange Editor, I could only edit the Title Border Text. All the node text isn't editable.
Using OCR in PDF-XChange, it converted all 5 pages in about 15 seconds.
I am using the paid-for version, so not sure if OCR is available in the free version.
I opened your PDF in Acrobat Pro and the text was editable.
This seems to be a Foxit issue, though as mentioned, you might want to use a TTF font if that's what Foxit needs.
ArialNarrow.ttf is a common replacement IIRC to ISOCP.shx
Just do a google you should be able to find a ISO.TTF font there are thousands of fonts out there. You open c:\Windows\fonts and drag the TTF onto it from memory. ISO3098B ?
If your lucky some one may have one already.