As far as I know beeilen must be used with a reflexive pronoun. But, as YetiCGN pointed out, that doesn't have to be sich since there are different reflexive pronouns depending on the subject: sich, mich, dich, uns, etc. In fact, other than sich, the reflexive pronouns look just like regular personal pronouns.
There are many verbs which do have both a ...
There are really two questions here. This first one is about the verb gefallen, which is similar to the English like, but there is a subject/object switch between the German and English verbs which is confusing if you're not used to it. The question linked in the comments covers this issue.
The other question is about the verb stattfinden, which is a ...
A student sitting in the front row of the classroom can understand/hear well what a math teacher is saying.
However, it is not certain that he also comprehends/grasps what the math teacher is saying.
Ein Schüler, der in der ersten Reihe des Klassenzimmers sitzt, kann gut verstehen/hören, was ein Mathematikleher sagt.
Es ist aber nicht sicher, dass er auch ...
As @infinitezero correctly comments, both variants are acceptable.
Sind is less favoured, since sein is a rather colorless auxiliary verb.
This auxiliary function can be seen from the slightly modified example:
Es sind interessante Gebäude in der Gegend verstreut.
Opposed to this geben (see meaning 14) at least indicates, that existence is talked about.