Looks like my T940 Astro Sonic chassis the only difference being the focus rect, mine uses the tube. Nevertheless what you're dealing with is low B+. Powering up the set and trying to "reform" a 50+ year old capacitor is a gamble at best. The best advice I can give before replacing any tubes or making any assumptions is to replace the power supply caps and check the dropping resistors on the side board. C105 is located near the power transformer, C107 and C130 are behind the HV cage, see the attached pics. My Astro Sonic has been in the family since early 1970 and in my care since 1984 when dad replaced it with a Zenith S-3... the Magnavox survives to this day. I'm using my T940 as an academic example here.
The only tube that has been a problem with these is V204 the 6MU8, the other issues you describe point to low B+ caused by bad/leaky capacitors behind R312, it's a resistor divider chain that supplies most everything in the set. Poor focus and low HV, limited brightness and what I can see in your pic is a lack of color caused by reduced voltage to the horiz section. This also provides the burst gate keying signal and when low will not open the color killer to allow the colorburst into the chroma bandpass amp. Low B+ will also cause weak audio and washed out contrast, the convergance & pincushion on the left reinforces my conclusion. Measuring the focus with a 40KV probe might make the meter wiggle some but the numbers are meaningless. HV ticking is leakage in the cage caused by dust that needs to be cleaned with some Windex and small towels after connecting a cleap lead to ground then the center contact of the 6BK4 plate cap, learned this the hard way at 14! Let things dry for an hour before power up.
Looking at your pix tube readings they are cathode currents and still strong. The voltages going to the pix are arbitrary, its the differentials between K&G1 that are important. A weak power supply is going to throw them all off. My T940 uses a 6MD8 triple triode for the R-Y G-Y B-Y drive and G-1 bias, I don't know what your T931 uses but it should have roughly 195 volts difference between cathode and grid-1. The picture tube section of the RCA Receiving Tube Manual details this better.
The T940 SAMS is Set 1109 Folder-1 and you mentioned having a Sams as well. I have over 40 years of experience with mine and it's posted here, look toward the bottom of the page
http://videokarma.org/showthread.php?t=273555 and if you look at Image34 it details how I addressed mounting the replacement capacitors.
What you have there is an EXCELLENT Magnavox console, a frosted front CRT without a cataract? WOW! Really complements your PortaColor.