Problem with page numbers,Thumbnails, and Sidebar Widgets

Hey Everyone !
Thank you very much for any help you can give me in advance.

I am having a hard time with a few points on my blog ,

My blog is located at https://fierth.com/a and i am using a theme that i modified only colors and subsituted graphics on. there is a “DEMO” page for the actual theme from its designer at https://wpthemedesigner.com/demo/

The problems i am experiencing are:

– when i slide widgets onto the sidebar they will completely throw off all of the pre existing sidebar menu items , is there a way i can create a sidebar pureloy of widgets and eliminate the ones that came with the theme ? if so ignore the next entry

– the text cloud in the sidebar will not appear

– post thumbnails are not automatically generating for some of the posts

– page numbers are not showing at the bottom of the main page , i currently have it set to show only 5 posts, i have posted about 15 test posts.

and just to be a pain in the rump there are two menus in the header , can i replace the lower one that already consists of categories , with somethign thats more graphic based and sleek ?

I really appreciate all of your help

Thanks ! Brian