Wenn du den Pakt erfolgreich geschlossen hast wird nicht mehr nachverhandelt. Alles danach ist quid pro quo. (Der Einsatz von Zauberbrand hebelt das leider arg aus.)
Bist du so wahnsinnig dich mehreren Patronen zu verschreiben? Nur zu.
Patronenzauber erhält man nur mit recht hohen Ergebnissen beim Pakt oder später durch Zufall, ggf. für eine mächtige Queste.
Der Zauber durch den Pakt darf gewählt werden, kann also jeder der drei sein. Und der zählt auch gegen das Maximum, lediglich Pakt und Anrufung zählt als ein Slot. (strenggenommen erwähnt das Regelwerk nirgends maximale, sondern nur beherrschte Zauber, Goodman hat das in einem Forenbeitrag so klargestellt. )
The "known spells" for wizards (per table 1-12 on page 50) is the maximum number of different spells that wizard can cast. Once a spell is "known" in this sense, it becomes a permanent choice and the wizard can't backtrack on it. This, a level 1 wizard may know four different spells (such as cantrip, charm person, magic missile, and mending). Note that those four initial spells are determined randomly (with some allowance for picking if the randomization is hard on the player; see page 124). Finally, note that Intelligence modifiers may increase the number of known spells (see page 18).
Invoke patron and patron bond count as one spell. If you get one, you automatically get the other, and they collectively count once. Patron bond is really a one-use prerequisite to invoke patron. (Well, you could use it twice, but that gets risky...) Patron bond could almost be the "intro paragraph" to invoke patron rather than its own spell; after all, one can't exist without another. There was a time in play testing where I had them count as different spells, but more than one player pointed out that "patron bond is like a waste of a spell slot; you use it once and then it's gone, and if you don't also have invoke patron it's totally useless." So they collectively count as one spell. Note that other patron spells aren't part of this "package deal" - other patron spells count as their own individual spell slots.
There are certain other rare circumstances which may also affect a wizard's known spells (e.g., the spell arcane affinity which is basically a mechanic for wizard specialization).
Now we get to the fun part: "spells in your spell book, on scrolls, and other reference materials" versus "spells known." As you guys know, DCC RPG is based on Appendix N, and there are many great tales of learning magical spells in Appendix N. Especially in Vance's Dying Earth series and the Harold Shea tales (as well as some Lovecraft) there are stories of wizards who know how to cast a handful of spells, going to great lengths to learn a single new spell. In many cases they acquire the spell's "recipe" - for example, they have the book in which the spell's rituals are written, and have acquired the materials, and are waiting for the right astrological confluence to cast the spell - but even after having everything in place, they just can't get it right. Or, they can't quite memorize it properly. So they may have reference for the spell (i.e., it's in their spell book) but they still can't cast it properly.
I suppose I should make this more clear somehow, and be careful in my use of the word "know"...but that dynamic is what I'm getting at it when discussing that a wizard may have possession of more spells than he cast. In play, your characters might find a scroll with two spells on it, and steal a spell book from a rival wizard with four more spells on it. So a wizard who levels up may actually have reference material for six additional spells. But such is his power level, ability to memorize, practice in casting, experience with nefarious powers, and so on, that he is only able to properly cast one of those six. And that one which he chooses to learn becomes his next "spell known" (per table 1-12) when he levels up.