Thanks for posting - great read! And felt like deja vue to me :-) I did pretty much the same project some years back with 34 tapes dating back to 1988 or so. I guess I was lucky that the actual digitization was a bit easier for me, because all my tapes were using Sony's 8mm tape system (Video8 / Hi8 / and Digital8). They were all playable on a 2005 Sony camcorder with a Firewire output, providing good quality DV files and no audio sync issues. However, deinterlacing was the big challenge for me. I remember http://www.100fps.com being a great resource on understanding the problem. Spent a lot of hours learning and perfecting my setup using VirtualDub, x264vfw (with as little compression as possible), AviSynth and QTGMC for deinterlacing http://avisynth.nl/index.php/QTGMC , and then another pass through Handbrake to get a much more reasonable file size and streamable format. I used Nextcloud for the web interface, but might switch to MediaGoblin now after reading your post. Didn't get around to splitting into clips actually - my family is happy enough with just being able to scrub/skip through tapes in Nextcloud's video player. I think it was about a 3 year on-and-off project.

Did the shop provide you with deinterlaced video?