How do Invert Sugars deter crystallization in Sucrose solutions?
I would like to know of how Invert Sugars physically interact with the other sugar molecules and prevent them from coming together


Glucose and fructose molecules (being essentially parts of sucrose) can merge into sucrose crystals during their formation, slowing or even completely stopping their growth in certain directions (if their concentration is high enough).


  even though they're not really resistant to crystallization (as pointed out above)


Glucose and fructose crystallization process is much slower than that of sucrose. From confectionery process's point of view, once the fast growing sucrose crystal structure is disrupted and its growth hindered no crystallization occurs.


  Why does the rate of cooling of a sugar solution affect its crystallization?


Because crystals' growth takes some time. If cooled fast, neither existing crystals will have a chance to grow, nor new seeds will appear. If cooled really fast, saturated sucrose syrup can even turn into glass with no crystals at all.

[literature]: Sgualdino, G., Aquilano, D., Vaccari, G., Mantovani, G., &amp; Salamone, A. (1998). Growth morphology of sucrose crystals. Journal of Crystal Growth, 192(1-2), 290–299.