Free flight/Micro RC

Shpould be fine. However most people converting these go the whole wy and fot a GWS IPS power plant - all that rubber...and it still doesn't last long.
The problem being basically that by the time the RC gear is in the weight is above what is really satisfcatory.
have a look in for lots of rubber conversions in the scale and parkfly areas.
Best is to use GWS IPS power plant, and a couole of small lithium polymer cells
Servos and receiver that you have are fine

ISTM that the Hitec kit is a bit heavy for a 35" rubber powered model. I asw in a ercent issue of MAN that someone (cirrus ?) is advertising true micro servos with a compatible rx as well. Weight of the servos was around the 3 gramme mark. I saw the complete outfit (2 servos + rx + esc) advertised in the same issue for $150.
Might be worth looking into.

If you're looking for real light stuff, check out
Bob

| I was thinking of using the Hitec HS-50 servos and the Hitec Feather | 4-channel receiver with 2 3V Lithium coin cell batteries to power it.
You can probably find a little bit smaller servos if you look. Don't have any specific models for you right now, however.
| invest in a better receiver, or will the Hitech's 1000' MAX range be | fine for these small birds?
1000'? You mean 500' max range.
The Hitec Feather is a crappy receiver. Don't buy it.
Instead, get the GWS 4P for about 1/2 the cost, and it has 1000' feet range and much better noise rejection. is a good place to get them.) It's even smaller than the Feather.
If you're looking to spend about $50 instead of $30, get the FMA Direct M5 receiver. It gives you the full 1 mile+ range and dual conversion noise rejection that you put in your larger planes, and only weighs a bit more than the GWS 4P. But for your plane, the 4P is probably just fine.