It looks to me like you're using external redirects when you should be using internal rewrites, and that you've got URLs confused with internal server filepaths.
Define the filepath to which your directory-index URL should resolve using the DirectoryIndex directive, as is
These two lines map requests for the URL example.com/ to the server filepath /index.php or /portal.php respectively. So a link to a URL
like example.com/Forums/ will invoke the file
at /Forums/index.php or /Forums/portal.php
"Fixing caps on folders" is also unclear, since "folders" implies a filepath, but you can simply rename those, so that should never be a problem. I suspect you mean you need to accept and correct capitalization errors in requested URL-path-parts, but I cannot be sure.
I can say that mod_rewrite and other .htaccess-usable modules are quite lousy (inefficient) at dealing with capitalization -- or with any kind of character-substitution. This is because no recursion is supported, so you can only "change characters" one at a time.
This is all server configuration stuff, and attention to correct terminology and details is required for success. So if you could put your questions in terms of what URL you want to resolve to what server filepath, and what URL you want to replace with what other URL in search results listings, it would greatly simplify things...
Also be aware that Redirect 301 /x http://www.example.com/y redirects a request for
...] to http:www.example.com/y
but it also redirects a request for
...] to http:www.example.com/yabc/def.ghi
The Redirect directive uses prefix-matching
and any part of the requested URL-path not specified in the matched prefix is "copied over" to the output URL. This is likely not what you want, and RedirectMatch would likely be a better choice. Also, if you have any RewriteRules whatsoever, or if you ever plan to use any, then do not use either Redirect or RedirectMatch, or you won't be able to control the order of execution of these directives ... it will be the server and not you that decides whether to process mod_alias Redirect and RedirectMatch directives first, or to process the mod_rewrite RewriteRules first... Mixing these two modules' directives can lead to all sorts of bizarre problems and devastation of your search ranking...
As above, this is server config stuff, and should be treated like dynamite... very old and unstable dynamite, in fact.