Can I use only input and select components?

It's possible, but you would need to import all the required parts of the styles for these components. To do it properly, we recommend to copy them from the node_modules/mdb-ui-kit/src/scss location directly to your project and import in the same way as CSS files. You can use our starter project to speed up the process: https://github.com/mdbootstrap/mdb-webpack-starter

Here is an example. In the index.scss file, comment out the mdb.min.css and import the scss parts:

// @import '~mdb-ui-kit/css/mdb.min.css';

@import '~mdb-ui-kit/src/scss/mdb.core.scss';
@import '~mdb-ui-kit/src/scss/bootstrap/forms';
@import '~mdb-ui-kit/src/scss/free/forms/form-control.scss';
@import '~mdb-ui-kit/src/scss/free/forms/form-select.scss';
@import '~mdb-ui-kit/src/scss/free/forms/form-check.scss';
@import '~mdb-ui-kit/src/scss/pro/variables.scss';
@import '~mdb-ui-kit/src/scss/pro/datepicker';
@import '~mdb-ui-kit/src/scss/pro/select.scss';

The same rule applies to the javascript files. You can import just individual modules:

import { Input } from 'mdb-ui-kit';
import { Select } from 'mdb-ui-kit';
import { Datepicker } from 'mdb-ui-kit';