I
think I
might see the problem. I believe it is possible that the only filter rule that matches non-ICMP traffic
between your two internal networks is "block all".
You can confirm this by adding "log" to all of your pass/block rules, and running tcpdump with pflog0. It will show which rule applies to any packet being examined.
In particular your "pass on" multiple interfaces by $Int_if macro may not be producing the results you want.
# pfctl -s rules will show you the ruleset with all expansions of macros and lists, and if you use
# pfctl -vs rules you get the rule numbers that are used with the pflog tcpdump output.
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A quick test is to change the block all rule to a pass all. If you can suddenly connect, you know that your PF configuration is the culprit.