Both are ok, but your first sentence is less written than spoken.

“Also is commonly used in writing, but is less common in speaking.” “Worddictionary.cambridge.org. org/grammar/british-grammar/also-as-well-or-too (

not to be repeated by my cousin).

To be is the infinitive form of this verb. All other forms you mentioned are just grammatical forms of this verb. As examples am/is/are are the present forms. I cannot say ‘I am’ because I am…! You ask about the meaning, there are many meaning because this verb can be the auxiliary, the part of phrases etc. It is very wide-spread word, therefore, it looks for you that it can be extremely often appear in some exam

tasks.