Issues with Add to cart, Checkout, Payment Modules, and Translation

[Prestashopify]

Hello,
I am new user of PrestaShop software for its eCommerce application. Very recent, I have encountered some issues after installing and configuration store setup with it.

I am using PrestaShop v. 1.7.5.2 with its Classic (default) theme for the shop. The store was fully functional and many of its features were enabled for this store. The display of products, add to cart, checkout, and delivery options were working seamlessly until early part of this week (~10-9-19)  when I checked its various features for operational integrity.

Three major issues are occurring right now:
1) The add to cart function works, but no products are visibly added to the cart, the checkout icon works, but there is no form for customer checkout, no payment options, and cart is empty with no products being added despite the add button on products working with confirmation page;

2) For payment preferences, the store was using PayPal standard and Braintree payments. There was major update to PayPal and Braintree modules (~9-1-19), when I tried to update them with uninstalling the older versions, I am unable to remove them completely and receive error messages;

3) The store is receiving errors of translation messages in AdminAdvparametersFeature and couple of User Deprecated errors in AdminMarketing and "sensio_framework-extra.router.annotations" and stating to use Sympony\Component\Routing\Annotation\Router

Further technical information can be provided upon review and any help to resolve these issues would be great. See JPG files (8)