I've definitely seen some of your vids on YT before, and welcome to MotK!
I approve of any crossover attempts of Touhou, TF2, and Gmod. Just see my
current avvy and FF2 bosses (in my sig) for proof
I'm going to guess that the models were chroma-keyed (ie. 'green screen') from MMD, and overlaid on top of the Gmod footage? If they're actual Gmod models I'd love to know the source.
I'd suggest putting your YT profile on your sig via the Forum Profile settings.
(and I still enjoy
Maxwell's Demopan way too much; put it as a Demopan intro song on the community TF2 server :V)