please transcribe these songs to tonic solfa

What are you offering to pay?

If you're willing to pay, I'd do it for ~$50 per part per song. It would take about 2 weeks. (I only looked at the biggest .PDF file.)

Since I would assume you're not interested in spending something on the order of ~$1,000 for the lot, you can do this yourself fairly easily (though it may take you a while). It might be worth it to try scanning the .PDF files, but I rather doubt that most 'text-to-notation' applications will be able to read the hand-written notes accurately. Instead, I would guess that you'll end up entering them manually. Easiest way to do this would be to create a "conductor's score" with all the instruments on a single page. Once complete, then create the Parts.

Changing it from normal notes to solfège is the easiest part of the whole thing: Select the notes and go to the Properties tab at upper left. Under Note, select Head. Slide down to the bottom and click the right arrow next to Show more to turn it down. The first item in the newly displayed properties is Notehead scheme. Set it to "Solfège fixed do" or "Solfège movable do" as you wish.

Since you have instruments here rather than singers, I am curious why you would want the solfège at all. (But none of my business.)