Is it possible to just clone the two sims as adults w/o any of their prior memories and relationship and be able to reuse them? And if so how does one go about doing that?
I had roughly the same thing happen in one of my neighbourhoods. If you can "see" the neighbourhood and the sims in it in SimPE, you can use SimPE's simsurgery tool to clone the two sims. I think this is generally the same as the MTS2 method.
In Simsurgery, scroll to your Sim in the 'Sim Pool'and highlight her/him with a single click. Then in the 'Patient Sim' window of the 'Sims Surgery Tool, click 'use'. Your Sim's picture should appear in the 'Patient Sim' window. Then click 'Export' at the top right in the 'Patient Sim' window. When prompted, give the sim file a filename you will remember (you probably want to delete it soon).
Do this for all the Sims you want to clone. When you're done, exit SimPE.
Open Sims2 Bodyshop (not the in-game CAS, but the separate Bodyshop program that comes with the game). Select "build/clone a sim". Read a book for a bit while bodyshop loads all the various sims templates. when it's done this, find one of the sims you just exported from SimPE. Clone this sim in bodyshop (yes, clone it again - the SimPE clones have all sorts of additional rubbish attached to them and they behave very strangely at times if you use them in the game, so it's safest to re-clone them in bodyshop. I find that bodyshop doesn't let me do anything with the sims anyway until I re-clone them).
You can edit your sim a bit now, if you like, or leave them the way they are. When you're done, "accept" or "save" your sim just like you would a newly created sim. I would now delete the SimPE clone since you now have a nice new shiny bodyshop clone.
Do this for all the sims you exported from SimPE.
Now close bodyshop and open the game. Go to whatever neighbourhood these sims are going to live in and open CAS. start to create a sim in the normal manner, but when the random sim comes up, instead of editing it, use the "select a sim" option. This opens up all the various sim templates available, including the ones you just cloned. Select your sim from here and then edit them as you would any other CAS sim (i.e. give them a name, star sign, aspiration, clothes, wider eyebrows, etc.). At this stage you can also choose any age for them (teen, adult, etc. if you don't want them to remain elders). If you want the sim to be roughly the same as in the previous neighbourhood, give them the same star sign and aspiration as they had before.
Save your sim.
If you want your sims to have the same personalities they had before, you will need to note their interests and personality traits (neatness, grouchiness, active/lazy, etc.). You can open SimPE again and edit these aspects of the sim to your liking, and then hit "commit". Make sure you save the neighbourhood package when you're done. Back up your neighbourhood before you do this, just to be safe.
Your sims should now be more-or-less identical to the ones from the old neighbourhood. The only thing missing from them will be their relationships and memories. When you create your couple you can certainly make them married at the CAS stage, but other memories they will have to get from experience.
Hope this helps.