1. Does a portfolio lender preapproval letter count as cash when searching leads? - It all depends on your purchase agreement. The As-Is sale and purchase agreement allows you to check the box saying you're paying cash, but that voids that ability for a financing contingency. You can say you're a cash buyer all day long, but if you want that safety net of being able to walk away from the contract if you get denied, then you wouldn't be a cash buyer. I recommend getting familiar with that contract. I've used it on 100% of resales, and only use a different contract when doing new construction, and using the builder's contract. This is also what you'll use when you list the home. I recommend marketing yourself as "well qualified buyer".
2. When searching leads, what keywords tell you they'll accept portfolio lending? (if PL doesn't =cash) Portfolio lending would be the check box marked "other" on the contract. Just explain to them it's not traditional financing, and say, feel free to call my lender to verify my strength as a buyer. You can still check the box other and be a strong buyer. Strength of the contract isn't always price, it's about control and the terms. Just make sure you use your due diligence period appropriately.
3. Depending on answers 1&2, is hard money lending usually the foot in the door for beginners low(er) on cash? It usually is because a lot of people getting into REI don't have the capital to do both, buying the property and funding the rehab. Hard money allows you to do both at the same time with the same loan. Lenders aren't dumb either, they are a good source of advice when they underwrite your property.
4. Do I need to ask for a preapproval letter each time I want to make an offer, or can I use one to submit for multiple leads to save time? Pre-approvals are going to be generic as they come. Listing agents (if one) is going to want one that's younger than 60 days old. They usually have an expiration date on it. It isn't also necessary, but it makes you seem more legitimate.
Good luck!
Watch out for those cash only deals. Property condition is a huge here, and whether or not the home can be insured. Honestly, that is one of the best approaches you can choose when thinking of buying the house. At the end of the flip, you have to sell it to an end buyer. That buyer is going to use traditional financing, and if you don't fix the roof, HVAC, plumbing, or electrical, you won't have an easy time selling that home. So make sure the homes systems are in good working, and insurable shape before you move forward. There are a lot of really terrible flips here, so there's opportunity to separate yourself from the competition, just make sure you budget correctly and make sure there's enough meat on the bone.