yes, you should be able to create a page programmatically in aem using the page manager api.See https://www.albinsblog.com/2014/12/programmatically-create-page-in-cq5.html#.ZEwxlnbMI2w for reference

Is manage tag for image inside folder is working for you? It seems in 2nd screenshot it’s looking for specific image 

Doesn’t changing the ootb index will have negative impact. If it’s really need to update the indexing best you can do is to create your own custom index

Similar question was answered on https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/excluding-properties-from-fulltext-lucene-index-searches-not/m-p/382778

The last installed one irrespective of version number

I believe you can implement lazy loading for images but not for js and css.

I believe latest install package/bundle always take precedence over the last install package/bundle with same name 

It should provide you the node path and not the page. Can you  check with random node present on the result if that’s value is present there or not. My be you need to look for other text in full text that describes or limits your search to the expected result 

path=/content/xxx fulltext=aem orderby=path p.limit=-1   above query works for me

Full text query is working for me in my local. The result is giving the authored node path.   are you referring to have the authored value as well in query results?