A few suggestions:
1. Move your intercom Route Group to the top of the list, so the dial pattern will be matched sooner.
2. Change the Route Group dial pattern to match the exact number of digits.
3. Delete all Facility Group dial rules except 4 and 7. If any extension numbers begin with 1, you'll need dial rule 2 as well.
4. Reduce the Interdigit Long and Short timers to 4 seconds. That seems to be a good compromise between dialing quickly, but allowing enough time for the user to complete dialing.
I'm migrating from decentralized 250s to a centralized 3300 platform, with fifty 250 sites networked. It took a lot of planning, especially the numbering plan. All of my 3300 extensions are 5-digit, beginning with 4. I changed the ARS feature code on the 250s to 4, then added a Route Group with dial pattern XXXX. This routes the calls to the intercom Facility Group, where I added a dial rule to insert a 4.
A 250 user dials 41234. Since 4 is the ARS feature code, it's treated like an outside call. 1234 matches dial pattern XXXX, so the call is sent to the correct Facility Group. A leading 4 is inserted, so 41234 is dialed on the intercom trunk group. Magically, extension 41234 on the 3300 rings.