Where to Buy Hosting Only and What to Do about Redirecting One Website to the Other

A client project got pushed back by several months, so I'm a bit rusty on the basics; but, we're ready to start back up now so I'm hoping y'all can help with a few questions...

My client has two domain names, purchased through Go Daddy.

I will be building out one of the domains with a WordPress website and redirecting the other to it (at least for the next few months, until she's ready to build out the second site).

Most of the hosting options I've found include a domain name... She already has the domain name, so I don't want to make her pay for extra domain names she doesn't need (although I don't think she has to use the included domain names... it just doesn't seem like a good deal if part of the package will go to waste... but, I digress). Bottom line: where can we get just the hosting part? Or, is it better to just go with the basic Go Daddy package they keep sending her promotional e-mails about?

Next, because she has two domains, I know that eventually she will need hosting for each... but (this may be a silly question), is there a way to redirect the second website to the first without paying for hosting on the second website until it's needed (i.e. ready to be built and stand alone)? Or, is it better to get an "upgraded" hosting package the supports "unlimited domains" from the get go?

Thanks in advance for any help y'all can provide!