Is it possible to come out of the IRR to go into a TPU to make up missing battle assemblies (BAs)?

Once you transfer to the IRR, you'll have to formally be attached to a unit in order to get drill credit (you don't get paid, but you can drill for points). As with any formal process, it will require paperwork, approvals, and coordination, so unless it is set-up before you transfer, it probably won't be by the time you ETS.

However, to your real question regarding VA eligibility.

Assuming you don't have any active duty time, the eligibility for the VA home loan is "six creditable years". If you've already completed your Annual Training with you unit, then it is very likely that you have accumulated enough points (50) to have a good year.

A typical reservist that attends all drills and their AT will have 78 points (48 from UTAs, 15 from AT, and 15 membership points). The membership points are prorated if you serve less than a full year, so if you have been in 7 months, each with a MUTA-4 for 28 points, and completed your AT (another 15 points) you'd have 43 points. Your would also have 8 membership points so that would put you at 51 points - a good year.

It's also VERY IMPORTANT to keep in mind that the points are calculated on your RYE date (Retirement Year Ending) and NOT the fiscal/physical year.

As for your bonus, you need to read your contract. Likely, the answer is that you will incur a debt for not completing the full terms of it (i.e., you only completed five of the six years so you will have to partially repay the bonus for not fully completing the sixth year).

Few things.
1) the VA Loan program can be matched economically if you shop around and find yourself a good broker. Bending over backwards to get the loan benefit really isn't worth the cost to get it.
2) If you are in the IRR now, and have no intention of doing 20 years to get a retirement then don't be so eager to get back into drilling status. You will be held accountable, and chances are better than not your chain of command is not going to work with you regarding your academy and very tenuous first years as a police officer.
3) If you do want to make 20+ years and you are still young enough then wait it out, stay in the IRR, and come back when you have your police career locked in, are under the protection of the police union and can leverage state and federal laws regarding any conflicts the USAR is going to absolutely cause.

You don't want to be in the middle of your probationary period of police work while put behind a rock and a hard place with the USAR. Neither employer is warm and understanding.

I was a career counselor for 15 years. Another option to consider is registering and completing correspondence courses for points. You can complete correspondence courses while in the IRR or in drilling status. You can complete a long course with a high point value or a short course with a lower point value, and take the test; you must pass within the 70% range. Successfully complete as many courses as needed with the applicable points to achieve a "SAT" year. i.e. First Aid Course is a short course & test, which was worth 4 points; which equals a MUTA 2 (one drill day). Other courses may be more points. You must apply the program, once you're enrolled you can select and complete courses on line. Courses have deadlines, you have to remain disciplined to make sure you meet them. See your unit career counselor, or Army Edu dept. They can help with the application process. I hope you find this helpful. Best wishes.