Sorry everyone but I forgot to add:

Currently, my budget allows only one new purchase so the XS/XF Racks are not an option. Neither is the MO-XF because I don't like the navigation or the knobs for layering.

My decision is narrowed down to either the Motif-XF or the Montage (only if I can load the Motif XF sounds into it).

Thanks!

There's no option for more storage since the flash memory is integrated (already on-board).

Did you happen to save an X3A of your old board?

https://yamahasynth.com/forum/load-xf-x3a-files-into-montage

If there are voices/performances which have issues - Yamaha is aware of the limitations of the converter (on board) and is working on it. I've mostly heard issues with inspiration in a flash and nothing specific about Motif XF preset voices. I think because presets you're not going to get a dump of the sample memory - which is the piece which is encoded in a difficult manner for Montage to resolve currently (inspiration in a flash).

Some of those (inspiration in a flash) performances/voices already reside in Montage presets.

Maybe look at the data list of Motif XF vs Montage and see if your top voices/performances (from Motif XF lingo) match up with the Montage. I usually use Foxit Reader (PDF) to extract text out of tables - and you can put this in a spreadsheet to match up items with the same names.

You'd use a USB stick to load Motif XF X3A or X3V files into Montage. There's a list of approved ones which basically means a smaller capacity drive with preferably USB 2.0. I.E. an inexpensive USB stick.

HOW HOW HOW do I get all of the motif XF Sounds and load it into my Montage? What accessories do I need? Is this aspect even available yet? Do I need to purchase more storage space or does it come "Ready-Set-Go"?

I need to make a decision on whether I'm need to find a used Motif-XF or get a Montage (only if I can add the Motif XF sounds) by next week.

How do I go about adding the Motif XF sounds into the Montage?

All of the Motif XF Preset Voices form the backbone of the internal Montage Library. The entity known in the XF as a Voice, occupies a single Part in a Montage Performance.

You can place 16 Parts in a single Performance, 8 of which you can play/trigger simultaneously via the keyboard.
You get 1920 factory Performances. And room for 640 User Performances.

If you owned an XF then you know much about working a Montage (it will not all be completely foreign to you).
The Montage is compatible with Motif XF/XS Voice, Waveform, and Arpeggio data.

Loading is handled in a similar fashion, via USB stick. Data can be loaded into User memory or to pre-installed FLASH ROM (Libraries)
The USER area is where you create your own Performances customized to your personal needs. It's your work area. There are 640 User Performance locations.
The Library memories let you keep the USER contents times 8.

If you think of the User area as your synth... you can carry eight other versions of your synth in the Library ROM area... always accessible.