Yes, renown impediments are based upon the number of active accounts only, and renown is gathered from activity, and is actually lost over time once a guild hits a certain level, so focusing all your characters into a single guild is the best way to develop renown.
You need spell components to cast most spells. There is a feat that can negate most of this, but it has significant costs. There is the omnispell dust, which seems to be a universal spell component, but I imagine it costs turbine points, which I would rather spend on many other things. Spell components can be bought from various places, I forget if they can be gotten on korthos, but there is an arcane shop in the harbour that sells spell components for level one and two spells.
Summon monster I, along with most of the summoning spells, and a few others, such as fire shield and teleport, have dialogue boxes that appear when you click on the spell. You can then click on the subspell in the dialogue box to cast that subspell, or drag the subspell onto the quick-bar to use like a normal spell. Summon monster has a limit of one monster at a time, if you cast the spell while a monster from a previous casting is still active, then the previous one will disappear and the new one will appear.