Illinois family house-flipping business: LLC vs LLLP vs LP with LLC as GP for taxes and liability?

My family is trying to structure a small house-flipping business in Illinois and I’m trying to understand what questions to ask a CPA/attorney before we set anything up.

Basic situation:

My dad has experience buying distressed properties, fixing them up, and reselling them. He would be the main operator doing/overseeing the rehab work, bids, contractors, property decisions, etc. His sons would mostly contribute capital and be passive investors. We may start with around $250k total family capital and use it to buy auction/foreclosure properties, rehab them, sell them, and reinvest into the next deal. Later we may hold some rentals, but the main activity right now is flipping for the next 3-5 years.

One concern is double taxation. We have looked at corporations, but if it’s taxed as a C corp and profits are distributed, we could have corporate tax plus shareholder tax. We are trying to avoid creating a structure that causes unnecessary double taxation.

The structures we’re trying to compare are:

1. Manager-managed LLC taxed as a partnership
2. Illinois LLLP, with dad as GP/operator and sons as limited partners
3. LP with an LLC as the general partner
4. Possibly S-corp taxation for some part of the business, if that makes sense

The main questions I’m trying to understand:

• If the sons are passive investors, would an LLLP or LP give cleaner self-employment tax treatment than a manager-managed LLC?
• Would the sons’ K-1 income from a manager-managed LLC potentially be subject to self-employment tax, even if they are passive?
• Would an Illinois LLLP be better than a plain LP because it gives liability protection to the general partner?
• Is an LP with an LLC as GP still better than an LLLP, or is that overkill for a small family flipping business?
• How should dad be paid if he is actively working in the business: guaranteed payments, distributions, W-2 through an S-corp, or something else?
• Since flips are usually dealer/inventory income, are there tax issues that make one structure clearly better or worse?
• If most profits are reinvested, how do people handle tax distributions so partners don’t owe tax without receiving cash?
• What type of CPA or attorney should we look for: real estate CPA, partnership tax CPA, business attorney, tax attorney, etc.?

I know Reddit is not a substitute for a CPA or attorney. I’m mainly trying to learn what structure is commonly used for this kind of “active operator + passive family investors” setup, and what red flags/questions I should bring to a professional.

Any advice from CPAs, attorneys, real estate investors, or people who have structured something similar would be appreciated.