Skip the Paracorr until you can appreciate the difference one makes and even then at f5 you will likely observe just as often without one. It’s very much a personal decision. The biggest improvement is seen with a well corrected eyepiece for the f5 light cone. Tele Vue offers a variety of well corrected eyepieces to suit your needs offering different apparent fields and eye relief.
See
https://www.televue.com/engine/TV3b_page.asp?id=154
and check out each link including the individual eyepiece links (from their home page). Plenty to read and learn with no obligation to buy.
Mainly what you are paying for in well corrected eyepieces is the improvement in the outer view towards to edge and the larger apparent field that you get but there are many other factors that contribute to a good eyepiece and a good view. If starting off on your observing journey you’ll be looking at targets in the middle of the field and won’t be too concerned with the outer edges (70% onwards). Nonetheless many eyepieces perform noticeably better than others even on axis but if you cannot get a good view in the centre then something is seriously wrong with the eyepiece if all other factors have been eliminated. By good I mean a clean view and not mushy. There are varying factors of good all the way up to exquisite.
At high power and if you have tracking and if looking at a small target then the centre is all you need to be concerned about. If no tracking then it’s nice to have a well corrected large apparent field so that you don’t have to nudge the telescope as often.
Eyepieces are very personal and what one person will enjoy and recommend based on their observing experience, equipment and eyes will not necessarily be the same for another person, their equipment and their eyes. If possible go to a star party and look through as many eyepieces as possible in similar telescopes to your own to get a feel for what works well and what you like.
I found this link reviewing the ES 4.7 vs Pentax 5mm that you may find interesting. See
https://stargazerslounge.com/topic/2...pentax-5mm-xw/
Not sure if the Meade 4.7 UWA is identical to the ES 4.7/82. 4.7mm would give you 320x which will be pushing it a lot on most nights as would 5mm at 300x. However given good seeing 300x is very doable in a good 12” telescope. I think your other option of 6.5mm may be more useful more often. I’ve not used the Morpheus so cannot comment on its performance.
It will come down to how much you want to spend and on what focal length you want to spend that on first. 13/9/7/5 or 13/10/8/6 or combination thereof would all be useful focal lengths with your telescope at the mid to high power end.
At the low power end it is just as interesting and for your telescope 31mm and 22mm in 82 deg is an option but this is where it starts getting expensive and that’s not even including 100 deg options. My first 2” low power eyepiece was a Celestron 32mm Erfle (many pronounce this as awful). It wasn’t awful until I used a 31mm Nagler and up until then it was perfectly adequate for many years, (only outer field is awful or poor in comparison). I still have it and occasionally use it but of course the Nagler wins on all accounts except weight which can be an issue especially with a Paracorr and I have sliding counterweights on my Newtonian for just that purpose.
Hope this was useful. Whatever you choose, enjoy!
Note you don’t have to spend a lot on eyepieces (or telescopes) to enjoy this hobby certainly not early in your journey and maybe not ever. Take your time and enjoy it!