assigning block of 5 static IP addresses to network devices

I was issued a block of 5 static IP addresses from Verizon. I have two
routers and 1 IP camera. I want each to have a static IP.  The WAN
port of the Verizon router connects to the internet service jack
installed by the Verizon installer. The Verizon tech told me to place
the IP address of the 2nd router ( 192.168.2.1 ) outside the DMZ of
the Verizon router ( 192.168.1.1 )  I tried this, setting something
called "DMZ host" in the config of the Verizon router to the
192.168.2.1 IP of the 2nd router ( Linksys E3000 ). But the Verizon
router said it could not see 192.168.2.1.   I called Linksys and they
completely confused me.  They said what I was wanting to do could not
be done.  When I suggested we replace the Verizon router with a 2nd
Linksys router I have, they said neither of my Linksys routers were
"modem/routers" and would not be able to connect to the web thru my
Verizon service.

I have an old device called an "ethernet mini hub".  dlink de-805tp.
It has 4 ports and I used it in the past to split 1 ethernet network
cable out to 3 network devices.  I disconnected the cable from WAN
port of the Verizon router and plugged it to the de-805tp mini hub. (
the other end of that cable goes the the Verizon internet service jack
). Then I connected cables from the WAN ports of each of the two
routers to the mini hub.  Set the static IP within the config of each
router. And sure enough it worked. Each router could connect to the
web. Each with its own static IP.

Is this legit to do?  It seems kind of obvious, but the techs from
both Verizon and Linksys did not suggest it.

Anyway, I have a problem.  I configed a Linksys IP camera to use a 3rd
static IP, plugged its cable into the de-805tp mini hub, and I can't
connect to it.  Also, from a PC connected to router 1, I cannot ping
the static IP of the 2nd router.  Which I guess is the same problem.
From my PC, I can connect to the web, ping the IP of google, but I
cannot ping the IP of my other static IPs, despite the fact that I
have a router on one of those addresses, and it is working.

What is preventing me from connecting to each of the network devices
with a static IP?