Implementing Coveo Search

Hi Support Team,

I want to implement Coveo search instead of Solr search. I am following your document "Creating a new search provider" https://community.telligent.com/community/8/w/api-documentation/45184/creating-a-new-search-provider . While using your suggested articles I have few questions. 

Query:

1. Can we use both search technique like Coveo search and Solr search. Like want to use coveo on one page and solr on another page in single application?

2. Is impacting if I implement new search technique like Coveo on whole site?

3. DO you have best approach to implement Coveo search in our site. I am sharing Coveo search technique.

Reference:

 https://docs.coveo.com/en/375/javascript-search-framework/coveo-javascript-search-framework-home