For your Threshold team you will only need a handful of figures to get started, five or six would be planty.
For the Lurkers it would all depend on what you want to use.
Cultists would be a kind of all-round bad huy type to get you started and from there you could add in what you fancied.
In the UK,North Star have quite a few things that you could use in the Artizan Thrilling Tales range, along with Copplestone Castings and Sally 4th also have the Thrilling Tales range and a selection from the Pulp Figures ranges.
Blind Beggar (my own range) have a few things that could work well too.