Hi paul,
Thank you for contacting us!
For your first question I have another code snippet that worked for me. If it doesn’t for you it will be best to create a code example for us.
1. Code snippet:
//In the onOpen event Handler

    onOpen($event: CustomEvent) {
        // event handling code goes here.
        const window = document.querySelector('smart-window')
        let dateInput = window.querySelectorAll('input')
        // outputed format of the date is MM/DD/YY
        //rest of the function code

And for your second question this is the default functionality of the checkbox but you can use the native method blur() to disable this appearance like so:

    const checkbox = document.getElementById('checkBox')
    checkbox.addEventListener('click', ()=>{

Let me know if that works for you.
Please, do not hesitate to contact us if you have any additional questions.
Best regards,
Yavor Dashev
Smart UI Team