Hi,
A newbie question)))
Is there any possibility to form a viable Rebels squad using two old starters and the Wave 1?)))
A Wave 1 squad
Most people are fine with using proxy cards, so if you are fine with that, yeah!
The ships are fine, it is just the upgrades that need some love.
Tarn Mison, Luke, Biggs, and Wedge are all fantastic X wing pilots, and Hobbie can really fly well with the new targeting astromech. Integrated Astromech is a new upgrade that is an autoinclude on all T65 X wings now.
Y wings love R3A2 and the new Twin Laser Turret, but Ion cannon turrets are still good too.
If you can't proxy any upgrade cards, or don't want to, I would just run as many cheap generics as you can. XXXY can be alright, but with modern upgrades you will be much happier.
Wedge (or Luke )+ R2D2
Biggs
2x rookies
Or
Luke
Garven
Biggs
Rokkie
Both seem better than XXXYY , but who knows ^^
I fly a list using all wave 1 pilots. Though the upgrade cards aren't.
Wedge Antilles
R2D2
Draw Their Fire
Shield Upgrade
Luke Skywalker
R5P9
Predator
Integrated Astromech
Biggs Darklighter
Veteran Instincts
R2D6
Integrated Astromech
My previous build of choice was
Luke Skywalker
Draw Their Fire
R2D2
Shield Upgrade
Wedge Antilles
Shield Upgrade
Biggs Darklighter
Shield Upgrade
and my friend played four xwings pretty regularly
Luke Skywalker
Draw Their Fire
R2D2
Shield Upgrade
3x Rookie Pilot
You could also run a pretty effective tie swarm
Howlrunner
Swarm Tactics
Dark Curse
Backstabber
4x Academy Pilot
Most people are fine with using proxy cards, so if you are fine with that, yeah!
Just don't try to enter a Store, Regional, National, or World Championship with proxied cards! 
Most people are fine with using proxy cards, so if you are fine with that, yeah!
Just don't try to enter a Store, Regional, National, or World Championship with proxied cards!
That's the point))) No proxies)))
Anyone can fly with proxies)))
I flew Wedge+Luke+Biggs squad at a local newbie tournament, but lost 3:1.
But that was my first official play))))
What about:
Wedge+R2+PtL
Luke+R2-D2+Determination
Wes+R2-F2+Determination
Wedge, Luke and Wes are good my friend plays them regularly. But he uses VI so that they can beat out other aces like soontir fel.