1. finding an instructor qualified to train in your Rv
It can be done. I took my BFR in my -9. It helped that the CFMEI I used was just about finished with his -7. Three weeks later I gave him some left seat time in my -9 in preperation for his first flight.

2. can a CFI fly for hire in an experimental aircraft
Yep. The aircraft isn't for hire, the CFI is.

3. can you get insurance to fly solo in your own experimental aircraft without a PPL
I haven't a clue. I would think it is all about the money.

4. can a designated examiner give you a check-ride in an experimental aircraft?
Yep. But, they have the right to decline.

The bigger issue would be getting someone (or letting someone else?) to fly off your 25 or 40 hours before you can get some duel in your new plane.
 
PPL first

One more data point. I got my PPL 3yrs ago, but wasn't aware RV's existed. (RV at end of this message)

My wife was a nervous participant. She said "flying is your thing, you're gonna need some hours before I feel safe going" Her first flight, I had 75hrs. At ~100hrs, we had a situation with turbulence over the Rockies and she didn't go again for 6months.:( This is tough when mine best friend didn't want to go. FAST FORWARD This past year we have several short XC's only on perfect weather days. She is finally enjoying the rides.

Since this is a hobby(my hobby)...I'm on the pay as you go budget and trying to maintain a normal outside lifestyle. Started the tail november 06, QB fuse/wings last year. Ordering the finish kit this spring.

Ensure your partner is onboard, before committing to a $80K hobby.

I only flew 50yrs last year, since my money goes to building fund and hadn't flown in 100 days. YIKES!!! so Yesterday we had a choice, go skiing or go flying, her pick. She said let's meet our friends for breakfast. I got the club C-182(her favorite), did a few laps around the pattern at KHLN to get current, flew to Townsend(8U8)to pick her up. Then we departed behind our friends(Rans S-7). Smooth as glass, 80mile vis to a great breakfast stop in Twin Bridges(7S1).

Great day topped off by meeting a Joel Haynes an RV-7A owner from Bozeman back at 8U8 when we returned. Joel has a nice simple -7a, O-360, FP which still needs paint(but was a beauty anyway).

Anyway. get that PPL, somedays it's better to be in the air than pounding rivets looking up.
 
Chase, there's a -7A kit in NC in the classifieds for sale. Good price. We could go get it:D, & tell your wife about it when we get home:D:D.

My father and I did just that with our RV-9 tail and wings. We just haven't gotten to the part about telling my wife. I think that as a widower he thinks this is funny.